PRIMEQUEST Servers
Integrating the robust performance of the Intel® Itanium® Processor together with a Fujitsu-designed memory and I/O sub-system have produced the best platform for running your mission-critical Red Hat, Novell SUSE Linux or Microsoft Windows Server applications. The scalability, flexible growth, and solid foundation of Symmetrical Multi-Processor (SMP) memory performance designed into PRIMEQUEST servers will provide you with the agility, efficiency, and continuity that your business requires in the Open Systems arena, meeting your needs now and well into the future.
* Enterprise-class integrated server designs
* Support for Red Hat Enterprise Linux and Novell SUSE Linux Enterprise Server
* Support for Microsoft Windows Server Enterprise Edition and Datacenter Edition
* Fault immunity using System Mirror Mode for class-leading availability
* The Flexible I/O capability supports balanced configurations
* Full Support for the extensive Itanium®-based solutions catalog
* A host of integrated facilities to reduce administrative complexity
o Redundant Management networks hosting SSL (Secure Sockets Layer) protocols
o Integrated Gbit switching and hub connections
o Integrated SCSI hard drives
o Integrated KVM/USB for simplified partition management
Monday, March 1, 2010
SPARC Enterprise Servers
SPARC Enterprise Servers
Fujitsu SPARC Enterprise® servers are highly reliable, easy to manage, vertically-scalable systems with all of the benefits of traditional mainframes and none of the associated cost, complexity, or vendor lock-in. In fact, Fujitsu SPARC Enterprise servers deliver mainframe-class system architecture at open systems prices. With symmetric multiprocessing (SMP) scalability from one to 64 dual processors (128 cores), memory subsystems as large as 2 TB, and high-throughput I/O architectures, Fujitsu SPARC Enterprise servers easily perform the heavy lifting required by consolidated workloads. Furthermore, Fujitsu SPARC Enterprise servers run the powerful Solaris™10 Operating System (OS) and include leading virtualization technologies. By offering Dynamic System Domains, eXtended system boards, Dynamic Reconfiguration, and Solaris Containers technology, Fujitsu SPARC Enterprise servers bring mainframe-class, sophisticated resource control to an open systems compute platform.
Massive compute power, resilient system architecture, flexible resource control features, and the advanced capabilities of the Solaris 10 OS combine in Fujitsu SPARC Enterprise servers to provide organizations a best-in-class enterprise platform. As an added benefit, Fujitsu SPARC Enterprise servers also offer improved performance over previous generations of Fujitsu servers, with a clear upgrade path that protects existing investments in software, training, and datacenter practices. By taking advantage of Fujitsu SPARC Enterprise servers, IT organizations can create a more powerful infrastructure, optimize hardware utilization, and increase application availability - resulting in lower operational cost and risk.
Reliability and innovation herald a new UNIX server age
Reliability and innovation herald a new UNIX server age
SPARC Enterprise maintains the innovation of SPARC/Solaris architecture by providing SPARC/Solaris continuity with enhanced features and performance. This new UNIX server - a combination of Fujitsu reliability technology and Sun Microsystems (Sun) innovation - provides a highly available computing platform, capable of adapting to rapid changes in the business environment and supporting evolution in enterprise computing.
SPARC Enterprise is the optimal solution for asset protection
SPARC/Solaris customers enthusiastically embraced PRIMEPOWER for its robust system availability and scalable performance. Based on that strong support, Fujitsu has continued to innovate and enhance the capabilities of UNIX severs, with enhanced reliability, flexibility and performance developments anticipating requirements well into the future.
In addition collaboration with Sun Microsystems has enabled much accelerated technological evolution on a global scale.
Now with a full line of high throughput servers, application platforms and data warehouse engines SPARC Enterprise provides more choice than ever for SPARC/Solaris customers.
Rapidly changing businesses, highly complex and diverse customer demands, can all be served by SPARC Enterprise. Its optimal solutions, world leading technologies and enterprise-class services will continues to present optimal solutions and, in most cases, best meet customer demands and support lowest possible ongoing costs.
Unix server
Unix server
A medium to large-scale computer system in a network that runs under Unix. Unix servers are widely used as application servers and database servers and are available from a variety of vendors, including Sun, IBM, HP and others. Sun has been the major proponent of Unix computer systems in the commercial world running on its SPARC processors, and The Santa Cruz Operation (SCO) has been the leading vendor of Unix on the Intel platform
A medium to large-scale computer system in a network that runs under Unix. Unix servers are widely used as application servers and database servers and are available from a variety of vendors, including Sun, IBM, HP and others. Sun has been the major proponent of Unix computer systems in the commercial world running on its SPARC processors, and The Santa Cruz Operation (SCO) has been the leading vendor of Unix on the Intel platform
UNIX Server Solutions - IBM Power Systems
UNIX Server Solutions - IBM Power Systems
Datatrend Technologies is your one-stop source for UNIX server solutions, utilizing a variety of UNIX versions, including IBM AIX. UNIX is a world-class operating system that supports a wide range of applications, and UNIX servers represent some of the most powerful, scalable, and flexible types of servers available.
We specialize in the IBM System p line of UNIX servers, widely considered the industry's leading UNIX server platform. IBM servers running AIX are the most adaptable, flexible, and agile systems available in the marketplace. The System p product line ranges from powerful desktop workstations to mission-critical, enterprise-class servers, as well as clusters and blade servers. In addition, IBM AIX is a respected version of the UNIX operating system, well known for its robustness.
In addition, Datatrend offers both leasing and purchase options. We always strive to provide you with the best possible pricing. Our solutions and services are tailored to your needs, and our aim is to improve your business by helping you save on operational costs and/or achieve efficiencies which help you grow your revenue and improve your bottom line.
Datatrend Technologies is your one-stop source for UNIX server solutions, utilizing a variety of UNIX versions, including IBM AIX. UNIX is a world-class operating system that supports a wide range of applications, and UNIX servers represent some of the most powerful, scalable, and flexible types of servers available.
We specialize in the IBM System p line of UNIX servers, widely considered the industry's leading UNIX server platform. IBM servers running AIX are the most adaptable, flexible, and agile systems available in the marketplace. The System p product line ranges from powerful desktop workstations to mission-critical, enterprise-class servers, as well as clusters and blade servers. In addition, IBM AIX is a respected version of the UNIX operating system, well known for its robustness.
In addition, Datatrend offers both leasing and purchase options. We always strive to provide you with the best possible pricing. Our solutions and services are tailored to your needs, and our aim is to improve your business by helping you save on operational costs and/or achieve efficiencies which help you grow your revenue and improve your bottom line.
Apache and Squid
Apache and Squid
Overview
Unix was developed by AT&T in the late 1960s and early 1970s, and it was freely distributed among a number of major universities during those years. When AT&T started charging for Unix, a number of developers tried to create clones of this operating system. One of these clones, Linux, was developed and released in the early 1990s.
Many of these same universities were also developing the network that evolved into the Internet. With current refinements, this makes Linux perhaps the most Internet-friendly network operating system available. The extensive network services available with Linux are not only the tops in their field, but they create one of the most powerful and useful Internet-ready platforms available today at any price.
Currently, Apache is the most popular Web server on the Internet. According to the Netcraft (www.netcraft.com) survey, which tracks the Web servers associated with virtually every site on the Internet, Apache is currently used by more Internet Web sites than all other Web servers combined. Apache is included with RHEL 5.
RHEL 5 also includes a number of other network services. The service that also focuses on Web access is the Squid Proxy Server, which caches frequently used pages locally.
This chapter deals with the basic concepts surrounding the use of these services and a basic level of configuration. In all cases, the assumption is that your network settings are correct and functioning properly. If you're having problems with your network configuration, read Chapter 7.
As for the RHCE exam, you may have to configure or troubleshoot either Apache or Squid. So as you read this chapter and look through the configuration files and exercises, be willing to experiment. And practice, practice, practice what you learn.
Overview
Unix was developed by AT&T in the late 1960s and early 1970s, and it was freely distributed among a number of major universities during those years. When AT&T started charging for Unix, a number of developers tried to create clones of this operating system. One of these clones, Linux, was developed and released in the early 1990s.
Many of these same universities were also developing the network that evolved into the Internet. With current refinements, this makes Linux perhaps the most Internet-friendly network operating system available. The extensive network services available with Linux are not only the tops in their field, but they create one of the most powerful and useful Internet-ready platforms available today at any price.
Currently, Apache is the most popular Web server on the Internet. According to the Netcraft (www.netcraft.com) survey, which tracks the Web servers associated with virtually every site on the Internet, Apache is currently used by more Internet Web sites than all other Web servers combined. Apache is included with RHEL 5.
RHEL 5 also includes a number of other network services. The service that also focuses on Web access is the Squid Proxy Server, which caches frequently used pages locally.
This chapter deals with the basic concepts surrounding the use of these services and a basic level of configuration. In all cases, the assumption is that your network settings are correct and functioning properly. If you're having problems with your network configuration, read Chapter 7.
As for the RHCE exam, you may have to configure or troubleshoot either Apache or Squid. So as you read this chapter and look through the configuration files and exercises, be willing to experiment. And practice, practice, practice what you learn.
Certification Objective 9.02-Apache Access Configuration
Certification Objective 9.02-Apache Access Configuration
Certification Objective 9.02-Apache Access Configuration
There are several parameters associated with security on the Apache Web server. The security of the server is enforced in part by firewalls and SELinux. Internal Apache security measures are associated with the main Apache httpd.conf configuration file.
Now that you've glanced at the configuration file, it's time to analyze it, and its associated directories, with a view toward security.
Basic Apache Security
You can modify the httpd.conf configuration file to secure the entire server or manage security on a directory-by-directory basis. Directory controls secure access by the server, as well as users who connect to the Web sites on the server. To explore the basics of Apache security, start with the first default active line in httpd.conf:
ServerTokens OS
This line looks deceptively simple; it limits what readers see about your Web server when you browse to a nonexistent page. If you don't use this command, outsiders can see whether you've loaded modules such as Perl, Python, and PHP. Sharing this knowledge can make your system more vulnerable. You can restrict access to the root directory on your Web server as shown here:
Options FollowSymLinks
AllowOverride None
This configures a very restrictive set of permissions. The Options FollowSymLinks line supports the use of symbolic links for Web pages. The AllowOverride None line disables any .htaccess files. Otherwise, .htaccess can allow others to administer your server, starting from the DocumentRoot directory. If .htaccess is in a subdirectory, such as /var/www/html/data/, the additional directives, if permitted by AllowOverride, would apply only to that directory.
Certification Objective 9.02-Apache Access Configuration
There are several parameters associated with security on the Apache Web server. The security of the server is enforced in part by firewalls and SELinux. Internal Apache security measures are associated with the main Apache httpd.conf configuration file.
Now that you've glanced at the configuration file, it's time to analyze it, and its associated directories, with a view toward security.
Basic Apache Security
You can modify the httpd.conf configuration file to secure the entire server or manage security on a directory-by-directory basis. Directory controls secure access by the server, as well as users who connect to the Web sites on the server. To explore the basics of Apache security, start with the first default active line in httpd.conf:
ServerTokens OS
This line looks deceptively simple; it limits what readers see about your Web server when you browse to a nonexistent page. If you don't use this command, outsiders can see whether you've loaded modules such as Perl, Python, and PHP. Sharing this knowledge can make your system more vulnerable. You can restrict access to the root directory on your Web server as shown here:
Options FollowSymLinks
AllowOverride None
This configures a very restrictive set of permissions. The Options FollowSymLinks line supports the use of symbolic links for Web pages. The AllowOverride None line disables any .htaccess files. Otherwise, .htaccess can allow others to administer your server, starting from the DocumentRoot directory. If .htaccess is in a subdirectory, such as /var/www/html/data/, the additional directives, if permitted by AllowOverride, would apply only to that directory.
Certification Summary-Networking services linux
Certification Summary-Networking services linux
Certification Summary
Networking services are an integral part of Red Hat Enterprise Linux. While most network services have been covered in other chapters, a few just don't fit neatly into other categories. Some are controlled through the xinetd daemon. SSH and DHCP are two other network services.
The Extended Internet Services Daemon, xinetd, governs the services configured though the /etc/xinetd.d directory. It controls services such as rsync, gssftp, and krb5-telnet, when installed.
Any network that is connected to an insecure network such as the Internet is vulnerable. Older protocols such as Telnet allowed passwords in clear text, which can be easily captured with tools such as Wireshark. The OpenSSH server can help you set up encrypted communication between computers.
DHCP allows a network administrator to manage IP address assignments of the computers on a LAN from a centralized server. DHCP requires some specialized setup on both the client and the server; however, it is easy to maintain once it is configured.
NTP services support time synchronization, which can keep changes such as moving to backup servers, load balancing, logs, and more, seamless to the end user. Clients can be configured with the Date/Time configuration tool or in /etc/ntp.conf. Configuring an NTP server requires specialized settings in /etc/ntp.conf.
Certification Summary
Networking services are an integral part of Red Hat Enterprise Linux. While most network services have been covered in other chapters, a few just don't fit neatly into other categories. Some are controlled through the xinetd daemon. SSH and DHCP are two other network services.
The Extended Internet Services Daemon, xinetd, governs the services configured though the /etc/xinetd.d directory. It controls services such as rsync, gssftp, and krb5-telnet, when installed.
Any network that is connected to an insecure network such as the Internet is vulnerable. Older protocols such as Telnet allowed passwords in clear text, which can be easily captured with tools such as Wireshark. The OpenSSH server can help you set up encrypted communication between computers.
DHCP allows a network administrator to manage IP address assignments of the computers on a LAN from a centralized server. DHCP requires some specialized setup on both the client and the server; however, it is easy to maintain once it is configured.
NTP services support time synchronization, which can keep changes such as moving to backup servers, load balancing, logs, and more, seamless to the end user. Clients can be configured with the Date/Time configuration tool or in /etc/ntp.conf. Configuring an NTP server requires specialized settings in /etc/ntp.conf.
Troubleshooting and System Maintenance Exam: RHCT Components
Troubleshooting and System Maintenance Exam: RHCT Components
There are five problems on the RHCT part of this section. You have to reconfigure your computer to address all five problems appropriately, within the first hour of your exam. In this exercise, you'll set up five different problems on the same computer or virtual machine.
Ideally, you'll have a friend or classmate who can help you prepare your computer. Assume that you have a network server with the RHEL installation files. When you install RHEL on this text computer, assume that you're on a network with an IP address of 172.16.32.0 (you can substitute a different network IP address if you desire). Include the K Desktop Environment in the installation. Then have your colleague take the following steps:
Install RHEL with at least 256MB of space that is unallocated to any partition. Create a /data directory on a logical volume.
Make sure RHEL boots from the command line, by setting the id directive in /etc/inittab to runlevel 1.
Set up Firefox to open automatically in the default GNOME Desktop Environment, using the Sessions manager (which you can open with the gnome-session-properties command in the GUI). Remember, this is user dependent, so you'll have to specify the user whose GUI the candidate is to configure.
Open /etc/X11/xorg.conf; create a typo in the Screen directive as defined in the first stanza. In my configuration, I changed
Screen 0 "Screen0" 0 0
to
Screen 0 "Screen" 0 0
In the /etc/sysconfig/network file, make sure that NETWORKING=no and HOSTNAME=localhost.
Disable SELinux; the simplest method, since you'll soon reboot, is to set SELinux=disabled in /etc/sysconfig/selinux.
In /etc/hosts, make sure the directive associated with the localhost IPv4 address is shown as:
127.0.0.1 localhost.localdomain localhost localhost
Run the poweroff command on the computer. It is now ready for this part of the exam.
Have the person taking the exam start the computer. Do not tell the candidate about the steps you took to prepare this computer. Tell him or her to
Allocate half of the free space on the current drive to a partition dedicated to the /test directory.
Make Linux boot into the GUI.
Address any problems you see the next time you boot Linux.
Configure the GNOME desktop to open a command line window for the selected user when you boot.
Assign a host name of enterprise5 to this system, and configure the network card to connect with DHCP.
There are five problems on the RHCT part of this section. You have to reconfigure your computer to address all five problems appropriately, within the first hour of your exam. In this exercise, you'll set up five different problems on the same computer or virtual machine.
Ideally, you'll have a friend or classmate who can help you prepare your computer. Assume that you have a network server with the RHEL installation files. When you install RHEL on this text computer, assume that you're on a network with an IP address of 172.16.32.0 (you can substitute a different network IP address if you desire). Include the K Desktop Environment in the installation. Then have your colleague take the following steps:
Install RHEL with at least 256MB of space that is unallocated to any partition. Create a /data directory on a logical volume.
Make sure RHEL boots from the command line, by setting the id directive in /etc/inittab to runlevel 1.
Set up Firefox to open automatically in the default GNOME Desktop Environment, using the Sessions manager (which you can open with the gnome-session-properties command in the GUI). Remember, this is user dependent, so you'll have to specify the user whose GUI the candidate is to configure.
Open /etc/X11/xorg.conf; create a typo in the Screen directive as defined in the first stanza. In my configuration, I changed
Screen 0 "Screen0" 0 0
to
Screen 0 "Screen" 0 0
In the /etc/sysconfig/network file, make sure that NETWORKING=no and HOSTNAME=localhost.
Disable SELinux; the simplest method, since you'll soon reboot, is to set SELinux=disabled in /etc/sysconfig/selinux.
In /etc/hosts, make sure the directive associated with the localhost IPv4 address is shown as:
127.0.0.1 localhost.localdomain localhost localhost
Run the poweroff command on the computer. It is now ready for this part of the exam.
Have the person taking the exam start the computer. Do not tell the candidate about the steps you took to prepare this computer. Tell him or her to
Allocate half of the free space on the current drive to a partition dedicated to the /test directory.
Make Linux boot into the GUI.
Address any problems you see the next time you boot Linux.
Configure the GNOME desktop to open a command line window for the selected user when you boot.
Assign a host name of enterprise5 to this system, and configure the network card to connect with DHCP.
Troubleshooting and System Maintenance Discussion
Troubleshooting and System Maintenance Discussion
Troubleshooting red hat linux
You shouldn't read this discussion until you've had a chance to try out the problems. I describe one possible solution to each problem. The solutions that you come up with can vary. The method you use doesn't matter; the result is what counts. As of this writing, in the Troubleshooting and System Maintenance section, you can't reinstall RHEL on the target computer and you can't go to the Internet for help during the exam.
Troubleshooting and System Maintenance Exam: RHCT-Level Problems
To pass either exam, you need to solve all five RHCT-level Troubleshooting and System Maintenance problems. In this simulation, you'll need to
Allocate half of the free space on the current drive to a partition dedicated to the /test directory.
Make Linux boot into the GUI.
Address any problems you see the next time you boot Linux.
Configure the GNOME desktop to open a command line window for the selected user when you boot.
Assign a host name of enterprise5 to this system, and configure the network card to connect with DHCP.
Address the problems that you've been given. In most cases, there are other ways to solve these problems. When you boot this system, the first thing you'll see is this:
sh-3.1#
You may already recognize this as the root prompt associated with runlevel 1. But you need to make Linux boot into the GUI, which means you need to make Linux boot into runlevel 5. And this is controlled in /etc/inittab, with the following directive:
id:5:initdefault:
Now you can reboot, or just run init 5 to move to that runlevel. But when you do, you'll see error messages related to the X Window, and are prompted for the root password to try to "fix" the problem. There's a key hint after you enter the password:
Data incomplete in file /etc/X11/xorg.conf
Undefined Screen "Screen" referenced by ServerLayout "Default Layout"
This suggests an error in the ServerLayout stanza in /etc/X11/xorg.conf. You could solve the problem here, but you're taken to the Display Settings Configuration tool, which is probably the quickest way to solve the problem. If successful, you'll see the GUI login screen.
When you log in, you'll see the Firefox Web browser. You could remove that from the applications that are automatically opened; all you need to do is make sure that a command line terminal is open. User applications in the GNOME desktop are driven by the GNOME Sessions tool and any existing .xinitrc file in that user's home directory. Add the command line terminal of your choice; the default for GNOME is gnome-session; xterm and konsole, if installed, are acceptable alternatives.
The simplest way to configure a host name and set networking to get address information from a DHCP server is with the GUI Network Configuration tool. You can also do this in /etc/sysconfig/network, /etc/hosts, and associated ifcfg-eth0 scripts.
Finally, to allocate free space to a new partition, you'll need to use the fdisk or parted utilities to create the partition, make sure it's the appropriate Linux file type, format it with a command such as mkfs.ext3, mount it to make sure it works, and add an appropriate directive to /etc/fstab to make sure it's mounted on /test the next time you boot Linux.
Troubleshooting and System Maintenance: RHCE-Level Problems
You'll see what's wrong when you try to log into RHEL. Be prepared to use the first RHEL installation CD to rescue this system. If you get instructions for a network source for the RHEL installation files, take careful notes. You've been told the following:
You will face a challenge during the boot process.
You'll want to make sure /boot is properly mounted.
You'll need to reduce the space available to the /tmp filesystem on a logical volume.
Make sure the NFS, sendmail, Apache, and vsFTP services are working and available to other systems.
(Yes, I know that's more than five problems.)
When you see your boot loader, probably GRUB, select your current version of RHEL.
Boot your RHEL computer. Watch the start messages carefully. In this case, you'll see the following messages, which could intimidate most Linux administrators:
setuproot: moving /dev failed: No such file or directory
setuproot: error mounting /proc: No such file or directory
setuproot: error mounting /sys: No such file or directory
Kernel panic - not syncing: Attempted to kill init!
Look at these messages carefully. If you're experienced with Linux, you'll recognize that RHEL experienced a kernel panic because it had trouble finding key directories. That suggests problems with the root directive in the GRUB configuration file.
Restart your computer. Insert the first RHEL installation CD, and set your computer to boot from this disk. At the installation prompt, type linux rescue. This assumes you have access to your installation source, just in case you need to reinstall the Linux kernel.
Proceed as if you're installing RHEL. Set up networking when prompted, as you may need access to some of the installation RPMs.
When you see the Rescue screen, click Continue. If it doesn't work, all that means is that Linux is having trouble mounting your system in read-write mode. In that case, you can select one of the other two options.
If successful, you'll see a note that your system has been mounted under /mnt/ sysimage. Click OK, and then run the chroot /mnt/sysimage command at the prompt.
Look for the /boot directory. You won't see anything there, which suggests that it wasn't mounted. So use a command like fdisk -l to review configured partitions, to find a logical candidate for /boot, and mount it. Just as one example, I show the result from my VMware system-your output is likely to be quite different:
Disk /dev/sda: 5368 MB, 5368709120 bytes
255 heads, 63 sectors/track, 652 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 14 104391 83 Linux
/dev/sda2 2677 652 5132767+ 8e Linux LVM
In this case, as the /boot directory can't be mounted on a logical volume, the only partition that could include the /boot directory files is /dev/sda1. So I follow up with this command (of course, if your system is different, substitute accordingly; if there are multiple possible /boot partitions, some trial and error may be required):
# mount /dev/sda1 /boot
Now you should be able to find the GRUB configuration file. As suggested earlier, there's a problem with the root directive:
root=LABEL=/boot
If you're as familiar as you should be with the GRUB configuration file, you'll see the error right away. The root directive in this line should point to the device associated with the top-level root directory. You'll find it in /etc/fstab:
/dev/VolGroup00/LogVol00 / ext3 defaults 1 1
This tells me what should be associated with the root directive:
root=/dev/VolGroup00/LogVol00
If the root directive in the GRUB configuration file is associated with a partition device, you might see something like LABEL=/ in /etc/fstab. In that case, you'd substitute the following:
root=LABEL=/
Alternatively, if you can't figure out the LABEL (with a command like e2label /dev/hda1), and the top-level root (/) directory is not on a logical volume, a LABEL may not have been assigned; just substitute the appropriate partition name:
root=/dev/sda2
Yes, you could also test this from the GRUB command line, as described in Chapter 3. But for this exercise, just reboot and see what happens. In rescue mode, type exit to get out of the chroot command, and then type the exit command again to reboot.
If you reboot, you'll note that the /boot directory still doesn't get mounted. Remember how mounting works-it depends on /etc/fstab. If you're observant, you'll see the directive associated with the /boot directory commented out. When you activate the command, /boot is mounted the next time you start this system. Alternatively, you can mount everything in /etc/fstab with the mount -a command.
At this time, make sure the noted services are active with a command like this:
# /etc/init.d/nfs status
When you see that NFS, vsFTP, Apache, and sendmail are not active, you could activate them and try rebooting. But if you're observant, you'll run a command like this:
# chkconfig --list httpd
httpd 0:off 1:off 2:on 3:on 4:on 5:on 6:off
You'll see that it's supposed to be on. This suggests another problem. If you know how the boot process works, you'll trace your way through /etc/inittab, and find the following problem directives:
id:4:initdefault:
#l4:4:wait:/etc/rc.d/rc 4
These suggest that this configuration uses a non-standard runlevel, and since the script that starts services is commented out, no services in that runlevel are started. So all you absolutely need to do is change the default runlevel.
Modify /etc/inittab to reflect an appropriate default runlevel, such as 5, and reboot. You'll see the desired services running now.
To make sure the noted services are available, run commands such as this:
# service httpd status
Make sure the noted services are available to others. Make sure SELinux is active, and open up access through a firewall. It's easiest to do both with the Security Level Configuration tool, which now allows you to create access to all the noted services.
If there are SELinux-related problems, they'll be shown with the SELinux troubleshooter, which can be started in the GUI with the sealert -b command. When there are problems, this tool often suggests solutions. If you have access to a remote system, say via SSH, it's best to log into the remote system. Then you can make sure you (and others on the network) have remote access to the noted services.
Finally, to reduce the amount of space available to a volume, you'll first need to back up the information in that volume. The ext2online command has been replaced with resize2fs, which can reduce the size of a volume. Alternatively, you can also back up the information on /tmp, unmount that directory, reduce the number of LV extents on the associated volume, remount /tmp, and restore the information. The key command is lvreduce; for example, the following command reduces the allocation for the noted volume to (approximately) 50MB:
Troubleshooting red hat linux
You shouldn't read this discussion until you've had a chance to try out the problems. I describe one possible solution to each problem. The solutions that you come up with can vary. The method you use doesn't matter; the result is what counts. As of this writing, in the Troubleshooting and System Maintenance section, you can't reinstall RHEL on the target computer and you can't go to the Internet for help during the exam.
Troubleshooting and System Maintenance Exam: RHCT-Level Problems
To pass either exam, you need to solve all five RHCT-level Troubleshooting and System Maintenance problems. In this simulation, you'll need to
Allocate half of the free space on the current drive to a partition dedicated to the /test directory.
Make Linux boot into the GUI.
Address any problems you see the next time you boot Linux.
Configure the GNOME desktop to open a command line window for the selected user when you boot.
Assign a host name of enterprise5 to this system, and configure the network card to connect with DHCP.
Address the problems that you've been given. In most cases, there are other ways to solve these problems. When you boot this system, the first thing you'll see is this:
sh-3.1#
You may already recognize this as the root prompt associated with runlevel 1. But you need to make Linux boot into the GUI, which means you need to make Linux boot into runlevel 5. And this is controlled in /etc/inittab, with the following directive:
id:5:initdefault:
Now you can reboot, or just run init 5 to move to that runlevel. But when you do, you'll see error messages related to the X Window, and are prompted for the root password to try to "fix" the problem. There's a key hint after you enter the password:
Data incomplete in file /etc/X11/xorg.conf
Undefined Screen "Screen" referenced by ServerLayout "Default Layout"
This suggests an error in the ServerLayout stanza in /etc/X11/xorg.conf. You could solve the problem here, but you're taken to the Display Settings Configuration tool, which is probably the quickest way to solve the problem. If successful, you'll see the GUI login screen.
When you log in, you'll see the Firefox Web browser. You could remove that from the applications that are automatically opened; all you need to do is make sure that a command line terminal is open. User applications in the GNOME desktop are driven by the GNOME Sessions tool and any existing .xinitrc file in that user's home directory. Add the command line terminal of your choice; the default for GNOME is gnome-session; xterm and konsole, if installed, are acceptable alternatives.
The simplest way to configure a host name and set networking to get address information from a DHCP server is with the GUI Network Configuration tool. You can also do this in /etc/sysconfig/network, /etc/hosts, and associated ifcfg-eth0 scripts.
Finally, to allocate free space to a new partition, you'll need to use the fdisk or parted utilities to create the partition, make sure it's the appropriate Linux file type, format it with a command such as mkfs.ext3, mount it to make sure it works, and add an appropriate directive to /etc/fstab to make sure it's mounted on /test the next time you boot Linux.
Troubleshooting and System Maintenance: RHCE-Level Problems
You'll see what's wrong when you try to log into RHEL. Be prepared to use the first RHEL installation CD to rescue this system. If you get instructions for a network source for the RHEL installation files, take careful notes. You've been told the following:
You will face a challenge during the boot process.
You'll want to make sure /boot is properly mounted.
You'll need to reduce the space available to the /tmp filesystem on a logical volume.
Make sure the NFS, sendmail, Apache, and vsFTP services are working and available to other systems.
(Yes, I know that's more than five problems.)
When you see your boot loader, probably GRUB, select your current version of RHEL.
Boot your RHEL computer. Watch the start messages carefully. In this case, you'll see the following messages, which could intimidate most Linux administrators:
setuproot: moving /dev failed: No such file or directory
setuproot: error mounting /proc: No such file or directory
setuproot: error mounting /sys: No such file or directory
Kernel panic - not syncing: Attempted to kill init!
Look at these messages carefully. If you're experienced with Linux, you'll recognize that RHEL experienced a kernel panic because it had trouble finding key directories. That suggests problems with the root directive in the GRUB configuration file.
Restart your computer. Insert the first RHEL installation CD, and set your computer to boot from this disk. At the installation prompt, type linux rescue. This assumes you have access to your installation source, just in case you need to reinstall the Linux kernel.
Proceed as if you're installing RHEL. Set up networking when prompted, as you may need access to some of the installation RPMs.
When you see the Rescue screen, click Continue. If it doesn't work, all that means is that Linux is having trouble mounting your system in read-write mode. In that case, you can select one of the other two options.
If successful, you'll see a note that your system has been mounted under /mnt/ sysimage. Click OK, and then run the chroot /mnt/sysimage command at the prompt.
Look for the /boot directory. You won't see anything there, which suggests that it wasn't mounted. So use a command like fdisk -l to review configured partitions, to find a logical candidate for /boot, and mount it. Just as one example, I show the result from my VMware system-your output is likely to be quite different:
Disk /dev/sda: 5368 MB, 5368709120 bytes
255 heads, 63 sectors/track, 652 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 14 104391 83 Linux
/dev/sda2 2677 652 5132767+ 8e Linux LVM
In this case, as the /boot directory can't be mounted on a logical volume, the only partition that could include the /boot directory files is /dev/sda1. So I follow up with this command (of course, if your system is different, substitute accordingly; if there are multiple possible /boot partitions, some trial and error may be required):
# mount /dev/sda1 /boot
Now you should be able to find the GRUB configuration file. As suggested earlier, there's a problem with the root directive:
root=LABEL=/boot
If you're as familiar as you should be with the GRUB configuration file, you'll see the error right away. The root directive in this line should point to the device associated with the top-level root directory. You'll find it in /etc/fstab:
/dev/VolGroup00/LogVol00 / ext3 defaults 1 1
This tells me what should be associated with the root directive:
root=/dev/VolGroup00/LogVol00
If the root directive in the GRUB configuration file is associated with a partition device, you might see something like LABEL=/ in /etc/fstab. In that case, you'd substitute the following:
root=LABEL=/
Alternatively, if you can't figure out the LABEL (with a command like e2label /dev/hda1), and the top-level root (/) directory is not on a logical volume, a LABEL may not have been assigned; just substitute the appropriate partition name:
root=/dev/sda2
Yes, you could also test this from the GRUB command line, as described in Chapter 3. But for this exercise, just reboot and see what happens. In rescue mode, type exit to get out of the chroot command, and then type the exit command again to reboot.
If you reboot, you'll note that the /boot directory still doesn't get mounted. Remember how mounting works-it depends on /etc/fstab. If you're observant, you'll see the directive associated with the /boot directory commented out. When you activate the command, /boot is mounted the next time you start this system. Alternatively, you can mount everything in /etc/fstab with the mount -a command.
At this time, make sure the noted services are active with a command like this:
# /etc/init.d/nfs status
When you see that NFS, vsFTP, Apache, and sendmail are not active, you could activate them and try rebooting. But if you're observant, you'll run a command like this:
# chkconfig --list httpd
httpd 0:off 1:off 2:on 3:on 4:on 5:on 6:off
You'll see that it's supposed to be on. This suggests another problem. If you know how the boot process works, you'll trace your way through /etc/inittab, and find the following problem directives:
id:4:initdefault:
#l4:4:wait:/etc/rc.d/rc 4
These suggest that this configuration uses a non-standard runlevel, and since the script that starts services is commented out, no services in that runlevel are started. So all you absolutely need to do is change the default runlevel.
Modify /etc/inittab to reflect an appropriate default runlevel, such as 5, and reboot. You'll see the desired services running now.
To make sure the noted services are available, run commands such as this:
# service httpd status
Make sure the noted services are available to others. Make sure SELinux is active, and open up access through a firewall. It's easiest to do both with the Security Level Configuration tool, which now allows you to create access to all the noted services.
If there are SELinux-related problems, they'll be shown with the SELinux troubleshooter, which can be started in the GUI with the sealert -b command. When there are problems, this tool often suggests solutions. If you have access to a remote system, say via SSH, it's best to log into the remote system. Then you can make sure you (and others on the network) have remote access to the noted services.
Finally, to reduce the amount of space available to a volume, you'll first need to back up the information in that volume. The ext2online command has been replaced with resize2fs, which can reduce the size of a volume. Alternatively, you can also back up the information on /tmp, unmount that directory, reduce the number of LV extents on the associated volume, remount /tmp, and restore the information. The key command is lvreduce; for example, the following command reduces the allocation for the noted volume to (approximately) 50MB:
Installation and Configuration
Installation and Configuration - red hat linux
Installation and Configuration-red hat linux,linux basics
The Installation and Configuration section is the second part of the Red Hat exam. If you're taking the RHCT, you're allowed 2.0 hours; if you're taking the RHCE, you're allowed 3.0 hours to install and configure Red Hat Enterprise Linux. You may get partial credit on some of these problems. You'll have access to the Red Hat Enterprise Linux installation files through a network server (the Exam Prep guide specifies a network installation). Once Red Hat Enterprise Linux is installed, you'll also have access to the man pages as well as any other documentation that you may have installed.
If you're studying for the RHCT, you can limit your focus to the RHCT-level skills; if you're studying for the RHCE, you'll need to complete all RHCT- and RHCE-level skills, in the time allotted.
No specific techniques or commands are required. Any reasonable technique is allowed if it gets you to the objective. For example, if you need to limit access to a specific service, you can use iptables, /etc/hosts.deny, or even SELinux. As long as it does the job, the configuration can get you full credit for that part of the exam.
You may need to limit access to network servers to specific users or other computers. However, this is a certification exam. Do not expect to have physical access to any other computer to test your settings. You will not have access to any outside networks such as the Internet.
If you're going for your RHCT, you'll need a grade of at least 70 percent in the RHCT-level skills. If you're going for your RHCE, you'll need a score of 70 percent on both sections.
Exam Watch
Read the entire Installation and Configuration exam before you finish installing RHEL. It's easier to configure RAID and logical volumes during the installation process. It can save time to install required servers during the installation process. And remember that you can start configuring RHEL through the CTRL-ALT-F2 console even while packages are being installed.
Most of you will find it difficult to complete this exercise within 3 hours. I've deliberately added extra difficulty to this second sample exam, which will hopefully ease your required effort during the actual RHCE exam. I've also split up this sample exam into RHCT- and RHCE-level skills for your convenience; it may not represent what you'll actually see on the exam. (I'm not allowed to tell you about it.)
If you're preparing for the RHCT exam, you can ignore the RHCE issues. If you're preparing for the RHCE exam, you'll have to meet all requirements in this section. Remember that the RHCE is inclusive of the RHCT.
Once you've mastered the skills in this book, try other variations. Practice with different scenarios until you become comfortable with the scenarios described in this book, as well as in the Red Hat Exam Prep guide.
Server Installation Problem: RHCT-Level Skills
Install Red Hat Enterprise Linux. The following conditions specify a connection to network servers, configured with some very specific partitions. Assume this computer gets its IP addressing information from a DHCP server. Let users start at a virtual console.
Install Linux with the partitions shown in Table B-1. The sizes shown are minimums. Make sure that the /home directory is configured in a RAID 5 software array with no spare partitions. Leave 1000MB of free, unallocated space on the hard drive. If your system has less available hard drive space, some adjustments may be possible, such as reducing the amount of space allocated to / and /usr to 2000MB each.
Table B-1: Required Partitions Filesystem
Size
/boot
100MB
/
4000MB
/home
1000MB
/var
1000MB
/usr
4000MB
Once RHEL is installed, you'll also want to configure the following:
A connection to a local printer
Active networking only during working hours (8:00 A.M to 5:00 P.M.)
An NIS client, on the biglan NIS domain
The automounter, configured to read the CD on the /misc/cd directory
Support for IP forwarding, as this computer may be a router in the future
Installation of the system-config-boot RPM
A Linux kernel, upgraded to the latest requirements
Configure a cross-functional group of users: avionics, vendor, seats, and galleys. Set them up as a group named pcplane. Create a /home/pcplane directory and allow them to share files without having to change permissions or ownership on any file they put in this directory. Do not give vendor read privileges on this directory. Limit each of these users to 100MB of files in this directory. Make it possible to create ACLs on the /home directory partition. Configure secret.doc (with a user and group owner of galleys) in /home/galleys with ACLs that allow user michael read-write access.
Set up appropriate partitions as a RAID 1 array (with one spare partition), dedicated to the /home/pcplane directory. While you could do this during the installation process, do so after installation, for the purpose of this exercise.
Server Installation Problem: RHCE-Level Skills
In this part of the exam, you'll configure a number of different servers on the RHEL system. Assume this computer is on a gateway between your LAN and an external network such as the Internet. Based on the configuration shown in Table B-1, set up /var on an LVM array.
Set up both a regular and a secure Web server. Make sure the home pages for each server are different. Limit access to within the LAN only, and to the users avionics, seats, and galleys. Create and activate a Web proxy server. Configure a Samba server that allows users to access their home directories from remote computers on the LAN. Create an NFS share, with full privileges, on your /tmp directory. Make sure SELinux settings support access to this share.
Set up an FTP server that supports only anonymous access, even from outside your LAN. Configure sendmail to support access from within the LAN; do not require address confirmation from a DNS server. Configure an incoming e-mail service that supports regular, non-secure IMAP4 connections. Activate the Secure Shell service, and allow access from inside and outside the LAN. Do not allow direct root logins through the Secure Shell connection.
Edit the Kickstart file that is created; set it up to be usable for other computers with an identical hardware configuration. The Kickstart file should also support the creation of the same partitions.
Installation Discussion
Since you can set up a Red Hat Enterprise Linux configuration in several ways, there is no one right answer for the listed requirements. But you should remember a few general concepts. It's normally fastest to include packages during the installation process. It's easiest (and generally faster) to set up RAID arrays and LVM groups during the installation process. Make sure that the services you set up are active at the appropriate runlevels.
You can set up DHCP addressing through the Red Hat installation program or in /etc/sysconfig/network. You'll also want to allow incoming connections to your SSH and FTP servers. You can do this with the Security Level Configuration tool, commands in /etc/hosts.allow and /etc/hosts.deny, directives in service-level configuration files, or even with appropriate iptables commands.
You can connect to a local printer by editing the files in /etc/cups or using the Printer Configuration utility. You can limit networking to working hours using appropriate cron jobs, stored in the /etc/cron.daily directory. Setting up an NIS client means activating the ypbind daemon and using domainname to designate the biglan NIS domain, or you can use the Authentication Configuration tool. Also, activate the SELinux allow_ypbind (Allow Daemons To Run With NIS) setting. Before the automounter works, you have to activate the autofs service as well as the appropriate commands in /etc/auto.master and /etc/auto.misc.
To support IP forwarding, you'll need to set the net.ipv4.ip_forward variable in /etc/sysctl.conf and activate it in the /proc/sys/net/ipv4/ip_forward file. You can install the RPMs of your choice, including system-config-boot, with the appropriate rpm -ivh packagename command; if there are dependencies, and you're connected to an appropriate repository, you can use the yum install packagename command. When you upgrade the Linux kernel, however, you should install it with rpm -i just in case the new kernel doesn't work. When you set up users in a special directory, don't forget to set up the directory with the SGID bit.
To make the /home directory work with quotas and ACL, you'll need to add the usrquota and acl options to the associated directive in /etc/fstab. Before you can configure quotas, you'll need to remount /home with at least the usrquota and acl settings. To give user michael read-write permissions to secret.doc in /home/galleys, set appropriate permissions to /home/galleys:
# chmod 701 /home/galleys/
and set appropriate permissions on /home/galleys/secret.doc:
# setfacl -m user:michael:rw- /home/galleys/secret.doc
Now that quotas are set, create appropriate quota configuration files with quotacheck -cuvm (or reboot); and then activate quotas with quotaon. You can then add quotas on a username with the edquota username command.
If you're setting up a RAID array after installation, you'll first need to configure appropriate partitions using fdisk or parted, and then collect them into an array with the right mdadm command. Remember that a RAID 1 array requires two partitions, and one spare is specified in the exam requirements (for a total of three RAID partitions). To make sure the configuration takes after you reboot, you'll need to configure the RAID array device, such as /dev/md0, with the specified directory, /home/pcplane, in the /etc/fstab configuration file.
Remember to set up a regular Web server in /etc/httpd/conf/httpd.conf and a secure Web server in /etc/httpd/conf.d/ssl.conf. You can set up index.html home pages in the appropriate DocumentRoot directories; plain text in these files is sufficient. To limit access to specific users, you'll want to set up a group with the htpasswd command and add the group name to the appropriate configuration file with the AuthUserFile command.
The Squid Web Proxy server is straightforward; it requires configuration of three commands in your /etc/squid/squid.conf file: visible_hostname, http_access, and acl. The default Samba server configuration already allows user access to their home directories, but you'll need to add passwords with the smbpasswd -a username command. But this won't work until you enable the Allow Samba To Share Users Home Directories option using the SELinux Management tool (or the corresponding setsebool -P samba_enable_home_dirs 1 command). You can set up an NFS share through /etc/exports or the NFS Server Configuration tool and the appropriate commands.
The vsFTP server already allows only anonymous access by default. To configure sendmail to support access within the LAN, you need to comment out the command in sendmail.mc that limits access to the local computer; it's well commented. Similarly, the command that allows connections to domain names unverified by DNS is active by default and need not be changed. The standard e-mail service for RHEL 5 that supports incoming connections is Dovecot. You can configure it in /etc/dovecot.conf. If you want to limit the protocols to IMAP4 connections, use the protocols directive; a helpful sample is included in the default version of this file. To activate the Secure Shell service (sshd), as well as the others, use the service command (or run the script from the /etc/init.d directory). For a hint on how to limit access to non-root users, look up the PermitRootLogin directive in the man page for sshd_config.
Make sure the SELinux booleans are compatible with these settings. If you use non-standard directories, you may have to apply the chcon command to make sure these directories have the same SELinux labels as the default directories. The SELinux Management Tool can help give access to appropriate services, as well as options such as home directory access
A default, partially disabled Kickstart file is available in the /root/anaconda-ks.cfg file. Once you've activated the partition command and saved it as ks.cfg, you can use it to install RHEL on other computers with a nearly identical hardware configuration. If you've saved it on a floppy, you can cite it at the installation boot prompt with the linux ks=hd:fd0:/ks.cfg command or on the local CD with the linux ks=cdrom:/ ks.cfg command.
Installation and Configuration-red hat linux,linux basics
The Installation and Configuration section is the second part of the Red Hat exam. If you're taking the RHCT, you're allowed 2.0 hours; if you're taking the RHCE, you're allowed 3.0 hours to install and configure Red Hat Enterprise Linux. You may get partial credit on some of these problems. You'll have access to the Red Hat Enterprise Linux installation files through a network server (the Exam Prep guide specifies a network installation). Once Red Hat Enterprise Linux is installed, you'll also have access to the man pages as well as any other documentation that you may have installed.
If you're studying for the RHCT, you can limit your focus to the RHCT-level skills; if you're studying for the RHCE, you'll need to complete all RHCT- and RHCE-level skills, in the time allotted.
No specific techniques or commands are required. Any reasonable technique is allowed if it gets you to the objective. For example, if you need to limit access to a specific service, you can use iptables, /etc/hosts.deny, or even SELinux. As long as it does the job, the configuration can get you full credit for that part of the exam.
You may need to limit access to network servers to specific users or other computers. However, this is a certification exam. Do not expect to have physical access to any other computer to test your settings. You will not have access to any outside networks such as the Internet.
If you're going for your RHCT, you'll need a grade of at least 70 percent in the RHCT-level skills. If you're going for your RHCE, you'll need a score of 70 percent on both sections.
Exam Watch
Read the entire Installation and Configuration exam before you finish installing RHEL. It's easier to configure RAID and logical volumes during the installation process. It can save time to install required servers during the installation process. And remember that you can start configuring RHEL through the CTRL-ALT-F2 console even while packages are being installed.
Most of you will find it difficult to complete this exercise within 3 hours. I've deliberately added extra difficulty to this second sample exam, which will hopefully ease your required effort during the actual RHCE exam. I've also split up this sample exam into RHCT- and RHCE-level skills for your convenience; it may not represent what you'll actually see on the exam. (I'm not allowed to tell you about it.)
If you're preparing for the RHCT exam, you can ignore the RHCE issues. If you're preparing for the RHCE exam, you'll have to meet all requirements in this section. Remember that the RHCE is inclusive of the RHCT.
Once you've mastered the skills in this book, try other variations. Practice with different scenarios until you become comfortable with the scenarios described in this book, as well as in the Red Hat Exam Prep guide.
Server Installation Problem: RHCT-Level Skills
Install Red Hat Enterprise Linux. The following conditions specify a connection to network servers, configured with some very specific partitions. Assume this computer gets its IP addressing information from a DHCP server. Let users start at a virtual console.
Install Linux with the partitions shown in Table B-1. The sizes shown are minimums. Make sure that the /home directory is configured in a RAID 5 software array with no spare partitions. Leave 1000MB of free, unallocated space on the hard drive. If your system has less available hard drive space, some adjustments may be possible, such as reducing the amount of space allocated to / and /usr to 2000MB each.
Table B-1: Required Partitions Filesystem
Size
/boot
100MB
/
4000MB
/home
1000MB
/var
1000MB
/usr
4000MB
Once RHEL is installed, you'll also want to configure the following:
A connection to a local printer
Active networking only during working hours (8:00 A.M to 5:00 P.M.)
An NIS client, on the biglan NIS domain
The automounter, configured to read the CD on the /misc/cd directory
Support for IP forwarding, as this computer may be a router in the future
Installation of the system-config-boot RPM
A Linux kernel, upgraded to the latest requirements
Configure a cross-functional group of users: avionics, vendor, seats, and galleys. Set them up as a group named pcplane. Create a /home/pcplane directory and allow them to share files without having to change permissions or ownership on any file they put in this directory. Do not give vendor read privileges on this directory. Limit each of these users to 100MB of files in this directory. Make it possible to create ACLs on the /home directory partition. Configure secret.doc (with a user and group owner of galleys) in /home/galleys with ACLs that allow user michael read-write access.
Set up appropriate partitions as a RAID 1 array (with one spare partition), dedicated to the /home/pcplane directory. While you could do this during the installation process, do so after installation, for the purpose of this exercise.
Server Installation Problem: RHCE-Level Skills
In this part of the exam, you'll configure a number of different servers on the RHEL system. Assume this computer is on a gateway between your LAN and an external network such as the Internet. Based on the configuration shown in Table B-1, set up /var on an LVM array.
Set up both a regular and a secure Web server. Make sure the home pages for each server are different. Limit access to within the LAN only, and to the users avionics, seats, and galleys. Create and activate a Web proxy server. Configure a Samba server that allows users to access their home directories from remote computers on the LAN. Create an NFS share, with full privileges, on your /tmp directory. Make sure SELinux settings support access to this share.
Set up an FTP server that supports only anonymous access, even from outside your LAN. Configure sendmail to support access from within the LAN; do not require address confirmation from a DNS server. Configure an incoming e-mail service that supports regular, non-secure IMAP4 connections. Activate the Secure Shell service, and allow access from inside and outside the LAN. Do not allow direct root logins through the Secure Shell connection.
Edit the Kickstart file that is created; set it up to be usable for other computers with an identical hardware configuration. The Kickstart file should also support the creation of the same partitions.
Installation Discussion
Since you can set up a Red Hat Enterprise Linux configuration in several ways, there is no one right answer for the listed requirements. But you should remember a few general concepts. It's normally fastest to include packages during the installation process. It's easiest (and generally faster) to set up RAID arrays and LVM groups during the installation process. Make sure that the services you set up are active at the appropriate runlevels.
You can set up DHCP addressing through the Red Hat installation program or in /etc/sysconfig/network. You'll also want to allow incoming connections to your SSH and FTP servers. You can do this with the Security Level Configuration tool, commands in /etc/hosts.allow and /etc/hosts.deny, directives in service-level configuration files, or even with appropriate iptables commands.
You can connect to a local printer by editing the files in /etc/cups or using the Printer Configuration utility. You can limit networking to working hours using appropriate cron jobs, stored in the /etc/cron.daily directory. Setting up an NIS client means activating the ypbind daemon and using domainname to designate the biglan NIS domain, or you can use the Authentication Configuration tool. Also, activate the SELinux allow_ypbind (Allow Daemons To Run With NIS) setting. Before the automounter works, you have to activate the autofs service as well as the appropriate commands in /etc/auto.master and /etc/auto.misc.
To support IP forwarding, you'll need to set the net.ipv4.ip_forward variable in /etc/sysctl.conf and activate it in the /proc/sys/net/ipv4/ip_forward file. You can install the RPMs of your choice, including system-config-boot, with the appropriate rpm -ivh packagename command; if there are dependencies, and you're connected to an appropriate repository, you can use the yum install packagename command. When you upgrade the Linux kernel, however, you should install it with rpm -i just in case the new kernel doesn't work. When you set up users in a special directory, don't forget to set up the directory with the SGID bit.
To make the /home directory work with quotas and ACL, you'll need to add the usrquota and acl options to the associated directive in /etc/fstab. Before you can configure quotas, you'll need to remount /home with at least the usrquota and acl settings. To give user michael read-write permissions to secret.doc in /home/galleys, set appropriate permissions to /home/galleys:
# chmod 701 /home/galleys/
and set appropriate permissions on /home/galleys/secret.doc:
# setfacl -m user:michael:rw- /home/galleys/secret.doc
Now that quotas are set, create appropriate quota configuration files with quotacheck -cuvm (or reboot); and then activate quotas with quotaon. You can then add quotas on a username with the edquota username command.
If you're setting up a RAID array after installation, you'll first need to configure appropriate partitions using fdisk or parted, and then collect them into an array with the right mdadm command. Remember that a RAID 1 array requires two partitions, and one spare is specified in the exam requirements (for a total of three RAID partitions). To make sure the configuration takes after you reboot, you'll need to configure the RAID array device, such as /dev/md0, with the specified directory, /home/pcplane, in the /etc/fstab configuration file.
Remember to set up a regular Web server in /etc/httpd/conf/httpd.conf and a secure Web server in /etc/httpd/conf.d/ssl.conf. You can set up index.html home pages in the appropriate DocumentRoot directories; plain text in these files is sufficient. To limit access to specific users, you'll want to set up a group with the htpasswd command and add the group name to the appropriate configuration file with the AuthUserFile command.
The Squid Web Proxy server is straightforward; it requires configuration of three commands in your /etc/squid/squid.conf file: visible_hostname, http_access, and acl. The default Samba server configuration already allows user access to their home directories, but you'll need to add passwords with the smbpasswd -a username command. But this won't work until you enable the Allow Samba To Share Users Home Directories option using the SELinux Management tool (or the corresponding setsebool -P samba_enable_home_dirs 1 command). You can set up an NFS share through /etc/exports or the NFS Server Configuration tool and the appropriate commands.
The vsFTP server already allows only anonymous access by default. To configure sendmail to support access within the LAN, you need to comment out the command in sendmail.mc that limits access to the local computer; it's well commented. Similarly, the command that allows connections to domain names unverified by DNS is active by default and need not be changed. The standard e-mail service for RHEL 5 that supports incoming connections is Dovecot. You can configure it in /etc/dovecot.conf. If you want to limit the protocols to IMAP4 connections, use the protocols directive; a helpful sample is included in the default version of this file. To activate the Secure Shell service (sshd), as well as the others, use the service command (or run the script from the /etc/init.d directory). For a hint on how to limit access to non-root users, look up the PermitRootLogin directive in the man page for sshd_config.
Make sure the SELinux booleans are compatible with these settings. If you use non-standard directories, you may have to apply the chcon command to make sure these directories have the same SELinux labels as the default directories. The SELinux Management Tool can help give access to appropriate services, as well as options such as home directory access
A default, partially disabled Kickstart file is available in the /root/anaconda-ks.cfg file. Once you've activated the partition command and saved it as ks.cfg, you can use it to install RHEL on other computers with a nearly identical hardware configuration. If you've saved it on a floppy, you can cite it at the installation boot prompt with the linux ks=hd:fd0:/ks.cfg command or on the local CD with the linux ks=cdrom:/ ks.cfg command.
Networking services
Certification Summary-Networking services linux
Certification Summary
Networking services are an integral part of Red Hat Enterprise Linux. While most network services have been covered in other chapters, a few just don't fit neatly into other categories. Some are controlled through the xinetd daemon. SSH and DHCP are two other network services.
The Extended Internet Services Daemon, xinetd, governs the services configured though the /etc/xinetd.d directory. It controls services such as rsync, gssftp, and krb5-telnet, when installed.
Any network that is connected to an insecure network such as the Internet is vulnerable. Older protocols such as Telnet allowed passwords in clear text, which can be easily captured with tools such as Wireshark. The OpenSSH server can help you set up encrypted communication between computers.
DHCP allows a network administrator to manage IP address assignments of the computers on a LAN from a centralized server. DHCP requires some specialized setup on both the client and the server; however, it is easy to maintain once it is configured.
NTP services support time synchronization, which can keep changes such as moving to backup servers, load balancing, logs, and more, seamless to the end user. Clients can be configured with the Date/Time configuration tool or in /etc/ntp.conf. Configuring an NTP server requires specialized settings in /etc/ntp.conf.
Certification Summary
Networking services are an integral part of Red Hat Enterprise Linux. While most network services have been covered in other chapters, a few just don't fit neatly into other categories. Some are controlled through the xinetd daemon. SSH and DHCP are two other network services.
The Extended Internet Services Daemon, xinetd, governs the services configured though the /etc/xinetd.d directory. It controls services such as rsync, gssftp, and krb5-telnet, when installed.
Any network that is connected to an insecure network such as the Internet is vulnerable. Older protocols such as Telnet allowed passwords in clear text, which can be easily captured with tools such as Wireshark. The OpenSSH server can help you set up encrypted communication between computers.
DHCP allows a network administrator to manage IP address assignments of the computers on a LAN from a centralized server. DHCP requires some specialized setup on both the client and the server; however, it is easy to maintain once it is configured.
NTP services support time synchronization, which can keep changes such as moving to backup servers, load balancing, logs, and more, seamless to the end user. Clients can be configured with the Date/Time configuration tool or in /etc/ntp.conf. Configuring an NTP server requires specialized settings in /etc/ntp.conf.
Kernel Services and Configuration
Kernel Services and Configuration
Overview
In this chapter, you'll learn how to upgrade standard kernels as well as configure, compile, and install your own custom kernels. You'll see several different ways to customize and optimize your kernel configuration for size and functionality. Finally, you'll examine recommended techniques for configuring and installing the kernel.
You'll also discover how to manage and modify special partitions associated with RAID arrays and LVM filesystems. While it's most efficient to configure these partitions during the installation process, you may have to modify them during your exam.
In several places in this chapter, I embed a command such as 'uname -r' in the name of a directory or file. This command substitutes itself in the name of directory or file. If unsure, run it in your own system.
Inside the Exam
Managing Kernels
As a competent Linux administrator, you need to know how to install, patch, and recompile kernels. It's easy to install a new kernel from an RPM, which makes it a reasonable requirement on the RHCT and RHCE exams. Early versions of the RHCE Exam Prep guide suggested that you need to know how to recompile the Linux kernel. But that was a long process! However, as the process is now much easier, I would not be surprised to see the requirement return for RHCEs in the near future.
In addition, the current Exam Prep guide suggests that you need to know how to do the following during the Installation and Configuration portion of both exams:
Properly update the Kernel package.
Use /proc/sys and sysctl to modify and set kernel run-time parameters.
RAID and LVM
The Exam Prep guide also describes skills associated with configuring RAID and LVM after installation. I've included it in this chapter to match the RH300 course outline more closely. While it's easiest (and therefore best) if you can configure RAID and LVM during the installation process, it's not always possible. If you make a mistake during the installation process, you don't need to start over. The Exam Prep guide suggests that during the Troubleshooting and System Maintenance portion of the exam, RHCTs need to know how to
Add new partitions, filesystems, and swap to existing systems.
RHCEs need to know how to
Add, remove, and resize logical volumes. Remember, if you're taking the RHCE exam, you also need to meet all RHCT requirements.
Overview
In this chapter, you'll learn how to upgrade standard kernels as well as configure, compile, and install your own custom kernels. You'll see several different ways to customize and optimize your kernel configuration for size and functionality. Finally, you'll examine recommended techniques for configuring and installing the kernel.
You'll also discover how to manage and modify special partitions associated with RAID arrays and LVM filesystems. While it's most efficient to configure these partitions during the installation process, you may have to modify them during your exam.
In several places in this chapter, I embed a command such as 'uname -r' in the name of a directory or file. This command substitutes itself in the name of directory or file. If unsure, run it in your own system.
Inside the Exam
Managing Kernels
As a competent Linux administrator, you need to know how to install, patch, and recompile kernels. It's easy to install a new kernel from an RPM, which makes it a reasonable requirement on the RHCT and RHCE exams. Early versions of the RHCE Exam Prep guide suggested that you need to know how to recompile the Linux kernel. But that was a long process! However, as the process is now much easier, I would not be surprised to see the requirement return for RHCEs in the near future.
In addition, the current Exam Prep guide suggests that you need to know how to do the following during the Installation and Configuration portion of both exams:
Properly update the Kernel package.
Use /proc/sys and sysctl to modify and set kernel run-time parameters.
RAID and LVM
The Exam Prep guide also describes skills associated with configuring RAID and LVM after installation. I've included it in this chapter to match the RH300 course outline more closely. While it's easiest (and therefore best) if you can configure RAID and LVM during the installation process, it's not always possible. If you make a mistake during the installation process, you don't need to start over. The Exam Prep guide suggests that during the Troubleshooting and System Maintenance portion of the exam, RHCTs need to know how to
Add new partitions, filesystems, and swap to existing systems.
RHCEs need to know how to
Add, remove, and resize logical volumes. Remember, if you're taking the RHCE exam, you also need to meet all RHCT requirements.
Monday, January 18, 2010
SanDisk Ultra II Mobile - flash memory card - 4 GB - MS PRO DUO
SanDisk Ultra II Mobile - flash memory card - 4 GB - MS PRO DUO
SanDisk Ultra II Mobile cards are high-performance memory cards ideal for mobile device enthusiasts looking for the best performance and quality to store their premium content. The newest generation of feature-rich mobile phones…
SanDisk Mobile Memory Kit flash memory card - 2 GB - microSD
SanDisk Mobile Memory Kit flash memory card - 2 GB - microSD
SanDisk is providing a single product with multiple adapters to be used in any SD, miniSD or microSD slot in any device. The microSD Mobile Memory Kit provides a flexible solution for mobile users who need a card for multiple SD…
Mobile Crossing WayPoint 205
Mobile Crossing WayPoint 205
The WayPoint is a new family of portable navigation systems by Mobile Crossing. The company is committed to providing the finest navigation systems for today's active drivers.If it is important to you that your GPS system works well…
HP iPAQ hw 6900 Mobile Messenger
Information technology professionals rely on HP quality to ensure maximum productivity. As the power of applications, processors, memory adapters and storage devices increases, high-end computer users are seeking ways to optimize…
socket soMo 650- M
The SoMo 650 makes small- to mid-sized deployments possible and affordable for a wide range of mobile business applications, including sales force automation, inventory management, patient care, merchandising, asset management.
Saturday, January 16, 2010
Nokia 5630
5630
Nokia 5630 XpressMusic is your connection to your closest friends & favourite music. Find great new sounds on-line with Nokia 5630 XpressMusic, & enjoy your music on-the-go. Nokia 5630 XpressMusic is a world of music. Enjoy crystal clear audio using the 3.5 mm AV connector, or get a big sound from the built-in stereo speakers of Nokia 5630 XpressMusic. "say and play" to access up to 16 GB of music with expandable memory. With your New Nokia 5630 XpressMusic See Snap & Share
Samsung E1080
Samsung E1080
Samsung E1080 - Slim and Sleek in your hand.Samsung E1080 - Easy to grip, the ergonomic 13.6mm is slim enough to fit anywhere, from the hand to pocke. Samsung E1080 is enhanced Mobile Power, 200-entry phonebook contains all your phone numbers for easy retrieval. Samsung E1080 is all about easy to use one hand operation. Fake call function of Samsung E1080 lets the phone automatically start ringing
Sony Ericsson T707
Sony Ericsson T707
Sony Ericsson T707 - The Light of Your LifeWith the eye-catching light effects of Sony Ericsson T707, you'll never miss a call - or be left in the dark. Give your best friends their own, unique pulsating light effects with Sony Ericsson T707. When a call from one of them comes in, you'll know who it is in a flash. The lustrous colours of the Sony Ericsson T707 add some extra glamour into your life. & there's magic, too - you control your Sony Ericsson T707 with a wave of your hand. Capture life as it happens around you with the 3.2 MP camera of Sony Ericsson T707 & post on your blog with just a few clicks
Nokia N95
Nokia N95
Quad Band slider with HSDPA, 5 Megapixel digital camera with Carl Zeiss optics, Video recording @ up to 30 fps, 3G video calling, Wi-Fi & Bluetooth, 60Mb built-in memory + MicroSD slot plus Built-in GPS receiver & mapping software, MP3 player + Stereo Fm radio, Up To 240 minutes Battery Talktime and Up To 215 hours Battery Standby Time
Tuesday, January 12, 2010
Java
The dominant mobile software platform is Java[citation needed] (in its incarnation as "Java Platform, Micro Edition", "Java ME", or formerly "J2ME" ). Java ME runs atop a Virtual Machine (called the KVM) which allows reasonable, but not complete, access to the functionality of the underlying phone. The JSR process serves to incrementally increase the functionality that can be made available to Java ME, while also providing Carriers and OEMs the ability to prevent access, or limit access to provisioned software.
BREW
In terms of use, Java ME is followed by BREW. BREW can provide complete control of the handset and access to all its functionality. However the power provided by native code with direct access to the handset APIs, has caused the BREW development process to be tailored largely towards recognized software vendors. While the BREW SDK (Software Development Kit) is freely available, running software on real mobile hardware (as opposed to the provided emulator) requires a digital signature which can only be generated with tools issued by a handful of parties, namely mobile content providers and Qualcomm themselves. Even then, the software will only work on test enabled devices.
Sunday, January 3, 2010
Nokia N800
The Nokia N800 Internet Tablet is a wireless Internet appliance from Nokia, originally announced at the Las Vegas CES 2007 Summit in January 2007. N800 allows the user to browse the Internet and communicate using Wi-Fi networks or with mobile phone via Bluetooth. The N800 was developed as the successor to the Nokia 770. It includes FM and Internet radio, an RSS news reader, image viewer and a media player for audio and video files.
CDMA Era SAMSUNG
CDMA Era (1996-1998)
Samsung developed its first CDMA mobile phone in March 1996, to coincide with the launch of CDMA service. The first digital handset, the SCH-100, was extra light and slim, and enabled clear voice communication. Before long, Samsung became the leader in the Personal Communications Service (PCS) market. It partnered with KTFreetel and Hansol PCS to provide PCS phones. Its first PCS phone, the SCH-1100, entered the market with innovative features, including a lightweight body, enhanced battery life, and the ability to capture delicate sounds. The design was targeted at the young generation because the young generation had emerged as a large and growing customer.
Samsung developed its first CDMA mobile phone in March 1996, to coincide with the launch of CDMA service. The first digital handset, the SCH-100, was extra light and slim, and enabled clear voice communication. Before long, Samsung became the leader in the Personal Communications Service (PCS) market. It partnered with KTFreetel and Hansol PCS to provide PCS phones. Its first PCS phone, the SCH-1100, entered the market with innovative features, including a lightweight body, enhanced battery life, and the ability to capture delicate sounds. The design was targeted at the young generation because the young generation had emerged as a large and growing customer.
5800 XpressMusic
Availability
Nokia announced the 5800 XpressMusic in London on October 2, 2008. The suggested retail price was €279 before taxes and network subsidies. The phone was made available Q4 2008 in Finland and other markets, specifically in Hong Kong, India, Indonesia, Malaysia, Russia, Spain, Taiwan, Thailand, Ukraine and United Arab Emirates. The phone missed the Christmas sales in more matured markets. Nokia has only commented that it needs time to customize the phone's software for operators in other markets. Analysts speculated the delay as a business manoeuvre not to butcher its existing product portfolio sales for Christmas as the phone is very competitively priced.
Nokia announced the 5800 XpressMusic in London on October 2, 2008. The suggested retail price was €279 before taxes and network subsidies. The phone was made available Q4 2008 in Finland and other markets, specifically in Hong Kong, India, Indonesia, Malaysia, Russia, Spain, Taiwan, Thailand, Ukraine and United Arab Emirates. The phone missed the Christmas sales in more matured markets. Nokia has only commented that it needs time to customize the phone's software for operators in other markets. Analysts speculated the delay as a business manoeuvre not to butcher its existing product portfolio sales for Christmas as the phone is very competitively priced.
N 95
The N95 has built-in Wi-Fi, with which it can access the Internet (through a 802.11b/g wireless network). The N95 can also connect to the Internet through a carrier packet data network such as UMTS, HSDPA, or EDGE. The web browser displays full web pages as opposed to simplified pages as on most other phones. Web pages may be viewed in portrait or landscape mode and automatic zooming is supported. The N95 also has built-in Bluetooth and works with wireless earpieces that use Bluetooth 2.0 technology and for file transfer.
Software and applications
Software and applications A phone with touchscreen feature. Mobile phone subscribers per 100 inhabitants 1997–2007The most commonly used data application on mobile phones is SMS text messaging, with 74% of all mobile phone users as active users (over 2.4 billion out of 3.3 billion total subscribers at the end of 2007). SMS text messaging was worth over 100 billion dollars in annual revenues in 2007 and the worldwide average of messaging use is 2.6 SMS sent per day per person across the whole mobile phone subscriber base (source Informa 2007).
categories of mobile phones
There are several categories of mobile phones, from basic phones to feature phones such as musicphones and cameraphones. There are also smartphones, the first smartphone was the Nokia 9000 Communicator in 1996 which incorporated PDA functionality to the basic mobile phone at the time. As miniaturisation and increased processing power of microchips has enabled ever more features to be added to phones, the concept of the smartphone has evolved, and what was a high-end smartphone five years ago, is a standard phone today. Several phone series have been introduced to address a given market segment, such as the RIM BlackBerry focusing on enterprise/corporate customer email needs; the SonyEricsson Walkman series of musicphones and Cybershot series of cameraphones; the Nokia Nseries of multimedia phones, the Palm Pre the HTC Dream and the Apple iPhone.
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