Installation of Red Hat Linux
Configuring a Network Installation
Configuring a Network Installation
Most Linux users can install Red Hat Enterprise Linux from a CD-ROM. During the installation portion of the Red Hat exam, you'll probably want to save time by installing RHEL 3 over a network on an NFS, HTTP, or FTP server. As you'll want to practice network installations, you'll want to set up a network server. For completeness, you can also install RHEL from ISO images on a local hard disk.
Configuring a Network Installation Server
Once you have the Red Hat installation CDs, configuring a network installation server is a fairly easy process. All you need to do is copy the files from each CD's /RedHat directory to a common directory, configure sharing on the directory, and then activate the NFS, FTP, or HTTP network.
Before you set up a network installation source, you'll need a partition with about 2GB of free space (or more). I'll illustrate the process for an NFS server, and explain the variations for FTP and HTTP servers.
Creating an NFS Installation Server
Configuring NFS Servers and Clients
The two key files to NFS are /etc/exports and /etc/fstab. Theexports file is configured on the server side and specifies which directories are to be shared with which clients and each client's access rights. The fstab file is configured on the client side and specifies which servers to contact for certain directories, as well as where to place them in the directory tree.
Setting Up the /etc/exports File
The /etc/exports file specifies which directories to share with which hosts on the network. You only need to set up this file on your NFS servers.
The /etc/exports file follows this format:
/directory/to/export host1(permissions) host2(permissions) host3(permissions) host4(permissions)
#
# Comments begin with the pound sign and must be at the start of
# the line
#
/another/dir/to/export host2(permissions) host5(permissions)
In this example, /directory/to/export is the directory you want to make available to other machines on the network. You must supply the absolute pathname for this entry. On the same line, you list the hosts and which permissions they have to access. If the list is longer than the line size permits, you can use the standard backslash (\) continuation character to continue on the next line.
You specify the names of the hosts in four ways:
- Their direct hostname.
- Using @ group, where group is the specific netgroup. Wildcard hosts in the group are ignored.
- Wildcards in the hostname. The asterisk (*) can match an entire network. For example, *.engr.widgets.com matches all hosts that end in .engr.widgets.com.
- IP subnets can be matched with address/netmask combinations. For example, to match everything in the 192.168.42.0network where the netmask is 255.255.255.0, you use 192.168.42.0/24 (that is, IP/netmask bits).
Each host is given a set of access permissions. The most significant ones are
- rw—Read and write access.
- ro—Read-only access.
- sync—This option requests that all file writes be committed to disk before the write request completes. The data is safer with this option because it is written to the disk more often; however, it does put more of a strain on the system's resources. By default this option is turned off and the server writes the data whenever it deems necessary.
- no_subtree_check—This option disables subtree checking. Subtree checking can improve reliability on directories that are exported as read-only or directories where files aren't often renamed. A good example of this is /usr. Subtree checking should be disabled on directories where files are frequently renamed. Home directories should have subtree checking disabled. Subtree checking is enabled by default.
- no_root_squash—Acknowledge and trust the client's root account.
If you are familiar with the export file configurations of other flavors of UNIX, you know that this process is not similar. Whether one is better than the other is a holy war discussion best left to Usenet newsgroups.
After you set up your /etc/exports file, run the exportfs command with the -r option:
exportfs -r
This sends the appropriate signals to the rpc.nfsd and rpc.mountd daemons to reread the /etc/exports file and update their internal tables.
In the following steps, I'll show you how to create a shared directory, copy the Red Hat installation files, and then set up the share through NFS. As NFS is the most efficient way to share files between Linux and Unix computers, I think it's the most likely option for network installations during the exam. You'll need the Red Hat Enterprise Linux installation CDs, or at least the ISO files associated with those CDs.
- Create a directory for your installation files. With the following command, I can create the /mnt/inst directory:
# mkdir /mnt/inst - Insert the first Red Hat Enterprise Linux installation CD into its drive. Mount it with the following command. (If all you have are the ISO files, say in the /tmp directory, substitute mount -t iso9660 -ro loop /tmp/firstcd.iso /mnt/cdrom.)
# mount /mnt/cdrom - Copy the required files from the first Red Hat Enterprise Linux installation CD.
# cp -ar /mnt/cdrom/RedHat /mnt/inst - Copy the .discinfo file from the first Red Hat Enterprise Linux installation CD. This is required if you want to use redhat-config-packages (also known as the Red Hat Package Management tool) to add software using this installation server after Linux is installed. (While there are a number of other files on the first RHEL 3 installation CD, .discinfo is the only file that's absolutely required for an installation server.)
# cp /mnt/cdrom/.discinfo /mnt/inst - Unmount the first Red Hat Enterprise Linux installation CD.
# umount /mnt/cdrom - Set up an NFS share. Add the following line to /etc/exports. You can do it with a text editor such as vi or the redhat-config-nfs utility (also known as the NFS Server Configuration tool)
/mnt/inst *(ro,sync) - Export the shared directory.
# exportfs -a - Make sure there's nothing blocking access to NFS. The default Red Hat Enterprise Linux firewall blocks access to an NFS server. While inelegant, the following command 'flushes,' or turns off the standard Linux firewall from the local computer.
# iptables -F - Now you can activate the NFS service. The following commands assume that it's already running (which you can check with the service nfs status command):
# service nfs stop # service nfs start - Finally, you can check the status of your share. If it's working, you should see the contents of the /etc/exports directory when you run the following command:
# showmount -e
When you install Red Hat Enterprise Linux from an NFS server, you'll need the name of the installation directory, in this case, /mnt/inst.
| On The Job |
For an NFS connection, you don't need to copy the files from a CD. If you've downloaded ISOs of the RHEL installation CDs, all you need to do is copy them to the shared NFS directory, in this case, /mnt/inst. However, this does not work for FTP or HTTP servers.
Scenario
To understand the benefits of NFS, consider an example. A school wants to set up a small computer lab for its students.
Downloading and installing RPMs isn't hard, "Installing Linux Software". When searching for the RPMs, remember that the filename usually starts with the software package name followed by a version number, as in yp-tools-2.8-3.i386.rpm.
The lab instructor did some research and created an implementation plan:
You have the scenario and the plan, it's time to get to work.
Configuring The NFS Server
Here are the steps to configure the NFS server in this scenario:
1. Edit the /etc/exports file to allow NFS mounts of the /home directory with read/write access.
/home *(rw,sync)
2. Let NFS read the /etc/exports file for the new entry, and make /home available to the network with the exportfs command.
[root@bigboy tmp]# exportfs -a
[root@bigboy tmp]#
3. Make sure the required nfs, nfslock, and portmap daemons are both running and configured to start after the next reboot.
[root@bigboy tmp]# chkconfig nfslock on
[root@bigboy tmp]# chkconfig nfs on
[root@bigboy tmp]# chkconfig portmap on
[root@bigboy tmp]# service portmap start
Starting portmapper: [ OK ]
[root@bigboy tmp]# service nfslock start
Starting NFS statd: [ OK ]
[root@bigboy tmp]# service nfs start
Starting NFS services: [ OK ]
Starting NFS quotas: [ OK ]
Starting NFS daemon: [ OK ]
Starting NFS mountd: [ OK ]
[root@bigboy tmp]#
After configuring the NFS server, we have to configure its clients, This will be covered next.
Configuring The NFS Client
You also need to configure the NFS clients to mount their /home directories on the NFS server.
These steps archive the /home directory. In a production environment in which the /home directory would be actively used, you'd have to force the users to log off, backup the data, restore it to the NFS server, and then follow the steps below. As this is a lab environment, these prerequisites aren't necessary.
1. Make sure the required netfs, nfslock, and portmap daemons are running and configured to start after the next reboot.
[root@smallfry tmp]# chkconfig nfslock on
[root@smallfry tmp]# chkconfig netfs on
[root@smallfry tmp]# chkconfig portmap on
[root@smallfry tmp]# service portmap start
Starting portmapper: [ OK ]
[root@smallfry tmp]# service netfs start
Mounting other filesystems: [ OK ]
[root@smallfry tmp]# service nfslock start
Starting NFS statd: [ OK ]
[root@smallfry tmp]#
2. Keep a copy of the old /home directory, and create a new directory /home on which you'll mount the NFS server's directory.
[root@smallfry tmp]# mv /home /home.save
[root@smallfry tmp]# mkdir /home
[root@smallfry tmp]# ll /
...
...
drwxr-xr-x 1 root root 11 Nov 16 20:22 home
drwxr-xr-x 2 root root 4096 Jan 24 2003 home.save
...
...
[root@smallfry tmp]#
3. Make sure you can mount bigboy's /home directory on the new /home directory you just created. Unmount it once everything looks correct.
[root@smallfry tmp]# mount 192.168.1.100:/home /home/
[root@smallfry tmp]# ls /home
ftpinstall nisuser quotauser smallfry www
[root@smallfry tmp]# umount /home
[root@smallfry tmp]#
4. Start configuring autofs automounting. Edit your /etc/auto.master file to refer to file /etc/auto.home for mounting information whenever the /home directory is accessed. After five minutes, autofs unmounts the directory.
#/etc/auto.master
/home /etc/auto.home --timeout 600
5. Edit file /etc/auto.home to do the NFS mount whenever the /home directory is accessed. If the line is too long to view on your screen, you can add a \ character at the end to continue on the next line.
#/etc/auto.home
* -fstype=nfs,soft,intr,rsize=8192,wsize=8192,nosuid,tcp \
192.168.1.100:/home/&
6. Start autofs and make sure it starts after the next reboot with the chkconfig command.
[root@smallfry tmp]# chkconfig autofs on
[root@smallfry tmp]# service autofs restart
Stopping automount:[ OK ]
Starting automount:[ OK ]
[root@smallfry tmp]#
After doing this, you won't be able to see the contents of the /home directory on bigboy as user root. This is because by default NFS activates the root squash feature, which disables this user from having privileged access to directories on remote NFS servers. You'll be able to test this later after NIS is configured.
Note: This automounter feature doesn't appear to function correctly in my preliminary testing of Fedora Core 3. See Chapter 29, "Remote Disk Access with NFS", for details.
All newly added Linux users will now be assigned a home directory under the new remote /home directory. This scheme will make the users feel their home directories are local, when in reality they are automatically mounted and accessed over your network.
Configuring The NIS Server
NFS only covers file sharing over the network. You now have to configure NIS login authentication for the lab students before the job is done. The configuration of the NIS server is not difficult, but requires many steps that you may overlook. Don't worry, we'll review each one in detail.
Note: In the early days, NIS was called Yellow Pages. The developers had to change the name after a copyright infringement lawsuit, yet many of the key programs associated with NIS have kept their original names beginning with yp.
Install the NIS Server Packages
All the packages required for NIS clients are a standard part of most Fedora installations. The ypserv package for servers is not. Install the package according to the steps outlined in Chapter 6,"Installing Linux Software".
Edit Your /etc/sysconfig/network File
You need to add the NIS domain you wish to use in the /etc/sysconfig/network file. For the school, call the domain NIS-SCHOOL-NETWORK.
#/etc/sysconfig/network
NISDOMAIN="NIS-SCHOOL-NETWORK"
Edit Your /etc/yp.conf File
NIS servers also have to be NIS clients themselves, so you'll have to edit the NIS client configuration file /etc/yp.conf to list the domain's NIS server as being the server itself or localhost.
# /etc/yp.conf - ypbind configuration file
ypserver 127.0.0.1
Start The Key NIS Server Related Daemons
Start the necessary NIS daemons in the /etc/init.d directory and use the chkconfig command to ensure they start after the next reboot.
[root@bigboy tmp]# service portmap start
Starting portmapper: [ OK ]
[root@bigboy tmp]# service yppasswdd start
Starting YP passwd service: [ OK ]
[root@bigboy tmp]# service ypserv start
Setting NIS domain name NIS-SCHOOL-NETWORK: [ OK ]
Starting YP server services: [ OK ]
[root@bigboy tmp]#
[root@bigboy tmp]# chkconfig portmap on
[root@bigboy tmp]# chkconfig yppasswdd on
[root@bigboy tmp]# chkconfig ypserv on
Table 30.1 lists a summary of the daemon's functions.
Table 30-1 Required NIS Server Daemons
Make sure they are all running before continuing to the next step. You can use the rpcinfo command to do this.
[root@bigboy tmp]# rpcinfo -p localhost
program vers proto port
100000 2 tcp 111 portmapper
100000 2 udp 111 portmapper
100009 1 udp 681 yppasswdd
100004 2 udp 698 ypserv
100004 1 udp 698 ypserv
100004 2 tcp 701 ypserv
100004 1 tcp 701 ypserv
[root@bigboy tmp]#
The ypbind and ypxfrd daemons won't start properly until after you initialize the NIS domain. You'll start these daemons after initialization is completed.
Initialize Your NIS Domain
Now that you have decided on the name of the NIS domain, you'll have to use the ypinit command to create the associated authentication files for the domain. You will be prompted for the name of the NIS server, which in this case is bigboy.
With this procedure, all nonprivileged accounts are automatically accessible via NIS.
[root@bigboy tmp]# /usr/lib/yp/ypinit -m
At this point, we have to construct a list of the hosts which will run NIS
servers. bigboy is in the list of NIS server hosts. Please continue to add
the names for the other hosts, one per line. When you are done with the
list, type a <control D>.
next host to add: bigboy
next host to add:
The current list of NIS servers looks like this:
bigboy
Is this correct? [y/n: y] y
We need a few minutes to build the databases...
Building /var/yp/NIS-SCHOOL-NETWORK/ypservers...
Running /var/yp/Makefile...
gmake[1]: Entering directory `/var/yp/NIS-SCHOOL-NETWORK'
Updating passwd.byname...
Updating passwd.byuid...
Updating group.byname...
Updating group.bygid...
Updating hosts.byname...
Updating hosts.byaddr...
Updating rpc.byname...
Updating rpc.bynumber...
Updating services.byname...
Updating services.byservicename...
Updating netid.byname...
Updating protocols.bynumber...
Updating protocols.byname...
Updating mail.aliases...
gmake[1]: Leaving directory `/var/yp/NIS-SCHOOL-NETWORK'
bigboy has been set up as a NIS master server.
Now you can run ypinit -s bigboy on all slave server.
[root@bigboy tmp]#
Note: Make sure portmap is running before trying this step or you'll get errors, such as:
failed to send 'clear' to local ypserv: RPC: Port mapper failureUpdating group.bygid...
You will have to delete the /var/yp/NIS-SCHOOL-NETWORK directory and restart portmap, yppasswd, and ypserv before you'll be able to do this again successfully.
Start The ypbind and ypxfrd Daemons
You can now start the ypbind and the ypxfrd daemons because the NIS domain files have been created.
[root@bigboy tmp]# service ypbind start
Binding to the NIS domain: [ OK ]
Listening for an NIS domain server.
[root@bigboy tmp]# service ypxfrd start
Starting YP map server: [ OK ]
[root@bigboy tmp]# chkconfig ypbind on
[root@bigboy tmp]# chkconfig ypxfrd on
Make Sure The Daemons Are Running
All the NIS daemons use RPC port mapping and, therefore, are listed using the rpcinfo command when they are running correctly.
[root@bigboy tmp]# rpcinfo -p localhost
program vers proto port
100000 2 tcp 111 portmapper
100000 2 udp 111 portmapper
100003 2 udp 2049 nfs
100003 3 udp 2049 nfs
100021 1 udp 1024 nlockmgr
100021 3 udp 1024 nlockmgr
100021 4 udp 1024 nlockmgr
100004 2 udp 784 ypserv
100004 1 udp 784 ypserv
100004 2 tcp 787 ypserv
100004 1 tcp 787 ypserv
100009 1 udp 798 yppasswdd
600100069 1 udp 850 fypxfrd
600100069 1 tcp 852 fypxfrd
100007 2 udp 924 ypbind
100007 1 udp 924 ypbind
100007 2 tcp 927 ypbind
100007 1 tcp 927 ypbind
[root@bigboy tmp]#
Adding New NIS Users
New NIS users can be created by logging into the NIS server and creating the new user account. In this case, you'll create a user account called nisuser and give it a new password.
Once this is complete, you then have to update the NIS domain's authentication files by executing the make command in the /var/yp directory.
This procedure makes all NIS-enabled, nonprivileged accounts become automatically accessible via NIS, not just newly created ones. It also exports all the user's characteristics stored in the /etc/passwd and /etc/group files, such as the login shell, the user's group, and home directory.
[root@bigboy tmp]# useradd -g users nisuser
[root@bigboy tmp]# passwd nisuser
Changing password for user nisuser.
New password:
Retype new password:
passwd: all authentication tokens updated successfully.
[root@bigboy tmp]# cd /var/yp
[root@bigboy yp]# make
gmake[1]: Entering directory `/var/yp/NIS-SCHOOL-NETWORK'
Updating passwd.byname...
Updating passwd.byuid...
Updating netid.byname...
gmake[1]: Leaving directory `/var/yp/NIS-SCHOOL-NETWORK'
[root@bigboy yp]#
You can check to see if the user's authentication information has been updated by using the ypmatch command, which should return the user's encrypted password string.
[root@bigboy yp]# ypmatch nisuser passwd
nisuser:$1$d6E2i79Q$wp3Eo0Qw9nFD/::504:100::/home/nisuser:/bin/bash
[root@bigboy yp]
You can also use the getent command, which has similar syntax. Unlike ypmatch, getent doesn't provide an encrypted password when run on an NIS server, it just provides the user's entry in the /etc/passwd file. On a NIS client, the results are identical with both showing the encrypted password.
[root@bigboy yp]# getent passwd nisuser
nisuser:x:504:100::/home/nisuser:/bin/bash
[root@bigboy yp]#
Configuring The NIS Client
Now that the NIS server is configured, it's time to configure the NIS clients. There are a number of related configuration files that you need to edit to get it to work. Take a look at the procedure.
Run authconfig
The
authconfig or the authconfig-tui program automatically configures your NIS files after prompting you for the IP address and domain of the NIS server.[root@smallfry tmp]# authconfig-tui
Once finished, it should create an /etc/yp.conf file that defines, amongst other things, the IP address of the NIS server for a particular domain. It also edits the /etc/sysconfig/network file to define the NIS domain to which the NIS client belongs.
# /etc/yp.conf - ypbind configuration file
domain NIS-SCHOOL-NETWORK server 192.168.1.100
#/etc/sysconfig/network
NISDOMAIN=NIS-SCHOOL-NETWORK
In addition, the authconfig program updates the /etc/nsswitch.conf file that lists the order in which certain data sources should be searched for name lookups, such as those in DNS, LDAP, and NIS. Here you can see where NIS entries were added for the important login files.
#/etc/nsswitch.conf
passwd: files nis
shadow: files nis
group: files nis
Note: You can also locate a sample NIS nsswitch.conf file in the /usr/share/doc/yp-tools* directory.
Start The NIS Client Related Daemons
Start the ypbind NIS client, and portmap daemons in the /etc/init.d directory and use the chkconfig command to ensure they start after the next reboot. Remember to use the rpcinfo command to ensure they are running correctly.
[root@smallfry tmp]# service portmap start
Starting portmapper: [ OK ]
[root@smallfry tmp]# service ypbind start
Binding to the NIS domain:
Listening for an NIS domain server.
[root@smallfry tmp]#
[root@smallfry tmp]# chkconfig ypbind on
[root@smallfry tmp]# chkconfig portmap on
Note: Remember to use the rpcinfo -p localhost command to make sure they all started correctly.
Verify Name Resolution
As the configuration examples refer to the NIS client and server by their hostnames, you'll have to make sure the names resolve correctly to IP addresses. This can be configured either in DNS, when the hosts reside in the same domain, or more simply by editing the /etc/hosts file on both Linux boxes.
#
# File: /etc/hosts (smallfry)
#
192.168.1.100 bigboy
#
# File: /etc/hosts (bigboy)
#
192.168.1.102 smallfry
Test NIS Access To The NIS Server
You can run the ypcat, ypmatch, and getent commands to make sure communication to the server is correct.
[root@smallfry tmp]# ypcat passwd
nisuser:$1$Cs2GMe6r$1hohkyG7ALrDLjH1:505:100::/home/nisuser:/bin/bash
quotauser:!!:503:100::/home/quotauser:/bin/bash
ftpinstall:$1$8WjAVtes$SnRh9S1w07sYkFNJwpRKa.:502:100::/:/bin/bash
www:$1$DDCi/OPI$hwiTQ.L0XqYJUk09Bw.pJ/:504:100::/home/www:/bin/bash
smallfry:$1$qHni9dnR$iKDs7gfyt..BS9Lry3DAq.:501:100::/:/bin/bash
[root@smallfry tmp]#
[root@smallfry tmp]# ypmatch nisuser passwd
nisuser:$1$d6E2i79Q$wp3Eo0Qw9nFD/:504:100::/home/nisuser:/bin/bash
[root@smallfry tmp]#
[root@smallfry tmp]# getent passwd nisuser
nisuser:$1$d6E2i79Q$wp3Eo0Qw9nFD/:504:100::/home/nisuser:/bin/bash
[root@smallfry tmp]#
Possible sources of error would include:
Try to eliminate these areas as sources of error and refer to the syslog /var/log/messages file on the client and server for entries that may provide additional clues.
Test Logins via The NIS Server
Once your basic NIS functionality testing is complete, try to test a remote login. Failures in this area could be due to firewalls blocking TELNET or SSH access and the TELNET and SSH server process not being started on the clients.
Logging In Via Telnet
Try logging into the NIS client via telnet if it is enabled
[root@bigboy tmp]# telnet 192.168.1.201
Trying 192.168.1.201...
Connected to 192.168.1.201.
Escape character is '^]'.
Red Hat Linux release 9 (Shrike)
Kernel 2.4.20-6 on an i686
login: nisuser
Password:
Last login: Sun Nov 16 22:03:51 from 192-168-1-100.simiya.com
[nisuser@smallfry nisuser]$
Logging In Via SSH
Try logging into the NIS client via SSH.
[root@bigboy tmp]# ssh -l nisuser 192.168.1.102
nisuser@192.168.1.102's password:
[nisuser@smallfry nisuser]$
In some versions of Linux, the NIS client's SSH daemon doesn't re-read the /etc/nsswitch.conf file you just modified until SSH is restarted. SSH logins, therefore, won't query the NIS server until this is done. Restart SSH on the NIS client.
[root@smallfry root]# service sshd restart
Stopping sshd:[ OK ]
Starting sshd:[ OK ]
[root@smallfry root]#
NIS Slave Servers
NIS relies a lot on broadcast traffic to operate, which prevents you from having an NIS server on a different network from the clients. You can avoid this problem on your local subnet by using slave servers that are configured to automatically synchronize their NIS data with that of the single master server.
You can also consider placing multiple NIS servers on a single subnet for the sake of redundancy. To do this, configure the NIS clients to have multiple NIS servers for the domain in the /etc/yp.conf file.
Configuring NIS Slave Servers
In this scenario, you need to add an NIS slave server named nisslave (IP address 192.168.1.254) to the NIS-SCHOOL-NETWORK NIS domain. You also must configure the NIS master server, bigboy, to push its database map information to the slave whenever there is an update. Here are the steps you need.
1. As you're referring to our servers by their hostnames, you'll have to make sure the names resolve correctly to IP addresses. This can be done either in DNS, when the hosts reside in the same domain, or more simply by editing the /etc/hosts files on both servers as seen in Table 30.2. Table 30-2 NIS Master / Slave /etc/hosts Files
2. Configure the NIS slave as a NIS client of itself in the /etc/yp.conf file, and configure the NIS domain in the /etc/sysconfig/network file as seen in Table 30.3. Table 30-3 NIS Master / Slave /etc/yp.conf Files
3. On the slave server, run ypbind so the slave can query the master server. [root@nisslave tmp]# service portmap start
Starting portmapper: [ OK ]
[root@nisslave tmp]# service ypbind start
Binding to the NIS domain:
Listening for an NIS domain server.
[root@nisslave tmp]#
[root@nisslave tmp]# chkconfig portmap on
[root@nisslave tmp]# chkconfig ypbind on
4. Optimize database map transfers by the NIS map transfer daemon, which should the started on both the master and slave.
[root@nisslave tmp]# service ypxfrd start
Starting YP map server: [ OK ]
[root@nisslave tmp]#
[root@nisslave tmp]# chkconfig ypxfrd on
[root@bigboy tmp]# service ypxfrd start
Starting YP map server: [ OK ]
[root@bigboy tmp]#
[root@bigboy tmp]# chkconfig ypxfrd on
5. Do a simple database query of the master from the slave using the ypwhich command with the -m (master) switch. You should get a listing of all the tables.
[root@nisslave tmp]# ypwhich -m
mail.aliases bigboy
group.bygid bigboy
passwd.byuid bigboy
rpc.bynumber bigboy
...
...
[root@nisslave tmp]#
6. Do an initial database download to the slave from the master with the ypinit command using the -s switch for a slave-type operation and specifying server bigboy as the master from which the data is to be obtained. You should see "Trying ypxfrd - success" messages. If the messages say "Trying ypxfrd - not running," then start ypxfrd on both servers.
[root@nisslave tmp]# /usr/lib/yp/ypinit -s bigboy
We will need a few minutes to copy the data from bigboy.
Transferring services.byservicename...
Trying ypxfrd ... success
Transferring group.byname...
Trying ypxfrd ... success
...
...
nisslave's NIS data base has been set up.
If there were warnings, please figure out what went wrong, and fix it.
At this point, make sure that /etc/passwd and /etc/group have
been edited so that when the NIS is activated, the data bases you
have just created will be used, instead of the /etc ASCII files.
[root@nisslave tmp]#
If your database is corrupt or your /etc/hosts files are incorrect, you'll get map enumeration errors as shown. Use the make command again to rebuild your database on the master when necessary.
[root@nisslave tmp]# /usr/lib/yp/ypinit -s bigboy
Can't enumerate maps from bigboy. Please check that it is running.
[root@nisslave tmp]#
7. Now that the data has been successfully downloaded, it's time to make the slave server serve NIS clients with ypserv.
[root@nisslave tmp]# service ypserv start
Starting YP server services:
[root@nisslave tmp]#
[root@nisslave tmp]# chkconfig ypxfrd on
8. Log on to the master server. Add the slave server to the master server's database map by editing the /var/yp/ypservers file on the master.
[root@bigboy yp]# cd /tmp
[root@bigboy tmp]# cd /var/yp/
[root@bigboy yp]# vi ypservers
Add nisslave to the file.
#
# File: /var/yp/ypservers
#
bigboy
nisslave
9. The make file in the /var/yp directory defines how the NIS server will build the database map and how the master will relate to the NIS slave. Make a copy of the master's make file for safekeeping.
[root@bigboy yp]# cp Makefile Makefile.old
10. Edit the make file to allow the master to push maps to the slave.
#
# File: /var/vp/Makefile
#
#
# Allow the master to do database pushes to the slave
#
NOPUSH=false
11. Use the make command to rebuild the database. The make command automatically pushes database updates to the servers listed in the /var/yp/servers file.
[root@bigboy yp]# make
gmake[1]: Entering directory `/var/yp/NIS-SCHOOL-NETWORK'
Updating ypservers...
YPPUSH: gethostbyname(): Success
YPPUSH: using not FQDN name
gmake[1]: Leaving directory `/var/yp/NIS-SCHOOL-NETWORK'
gmake[1]: Entering directory `/var/yp/NIS-SCHOOL-NETWORK'
Updating netid.byname...
YPPUSH: gethostbyname(): Success
YPPUSH: using not FQDN name
gmake[1]: Leaving directory `/var/yp/NIS-SCHOOL-NETWORK'
[root@bigboy yp]#
12. On the slave server, create a cron file in the /etc/crond.d directory, in this case named nis_sync, that will run periodic database downloads from the master server. This helps to ensure that the slave servers have current databases even if they miss updates from the master in the event the school goes offline for maintenance. Restart the cron daemon so that the configuration in this file becomes active.
[root@nisslave yp]# vi /etc/cron.d/nis_sync
#
# File: /etc/cron.d/nis_sync
#
20 * * * * /usr/lib/yp/ypxfr_1perhour
40 6 * * * /usr/lib/yp/ypxfr_1perday
55 6,18 * * * /usr/lib/yp/ypxfr_2perday
[root@nisslave yp]# service crond restart
That's a lot of work but it's still not over. There is one final configuration step that needs to be done on the NIS clients before you're finished.
Configuring NIS Clients With Slaves
Edit the /etc/yp.conf file on all the clients to include nisslave, and restart ypbind.
#
# File: /etc/yp.conf (Smallfry)
#
domain NIS-SCHOOL-NETWORK server 192.168.1.100
domain NIS-SCHOOL-NETWORK server 192.168.1.254
[root@smallfry tmp]# service ypbind restart
Shutting down NIS services: [ OK ]
Binding to the NIS domain: [ OK ]
Listening for an NIS domain server..
[root@smallfry tmp]#
Changing Your NIS Passwords
You should also test to make sure your users can change their NIS passwords from the NIS clients with the yppasswd command. The process is different whether there is only a single NIS master or a master-slave server relationship.
When There Is Only An NIS Master
When there is only a single NIS server, password changes can be made only on the NIS server using the yppasswd command.
Users Changing Their Own Passwords
Users can change their passwords by logging into the NIS server and issuing the yppasswd command.
[nisuser@bigboy nisuser]$ yppasswd
Changing NIS account information for nisuser on bigboy.my-site.com.
Please enter old password:
Changing NIS password for nisuser on bigboy.my-site.com.
Please enter new password:
Please retype new password:
The NIS password has been changed on bigboy.my-site.com.
[nisuser@bigboy nisuser]$
User "Root" Changing Passwords
The root user can change other users' passwords issuing the yppasswd command with the -p switch that specifies the username that needs the change.
[root@bigboy tmp]# yppasswd -p nisuser
Changing NIS account information for nisuser on bigboy.my-site.com.
Please enter root password:
Changing NIS password for nisuser on bigboy.my-site.com.
Please enter new password:
Please retype new password:
The NIS password has been changed on bigboy.my-site.com.
[root@bigboy tmp]#
When There Is A NIS Master / Slave Pair
With an NIS master and slave pair configuration, passwords can be changed on the NIS clients or the NIS slave, but not on the NIS master.
Possible Password Errors
There are a number of unexpected errors you may find when changing passwords - errors that have nothing to do with bad typing.
Segmentation Faults
Running the yppasswd command on the wrong client or server depending on your NIS master and slave configuration can cause segmentation fault errors. (Make sure you follow the chapter's guidelines for password changes!) Here are some sample password change failures on an NIS client with only one NIS master server.
[nisuser@smallfry nisuser]$ yppasswd
Segmentation fault
[nisuser@smallfry nisuser]$
[root@smallfry root]# yppasswd -p nisuser
Segmentation fault
[root@smallfry root]#
Daemon Errors
The yppasswdd daemon must be running on both the client and server for password changes to work correctly. When they aren't running, you'll get errors.
[root@smallfry etc]# yppasswd -p nisuser
yppasswd: yppasswdd not running on NIS master host ("bigboy").
[root@smallfry etc]#
You'll also get a similar error if you attempt to change an NIS password on an NIS master server in a master and slave configuration.
Considerations For A Non NFS Environment
In many cases NFS, isn't used to create a centralized home directory for users and, therefore, you'll have to create it on each NIS client and not on the server.
This example creates the home directory for the NIS client, smallfry. After doing this, you have to copy a BASH login profile file into it and modify the ownership of the directory and all the files to user nisuser.
Logins should proceed normally once this has been done and all the other steps have been followed.
[root@smallfry tmp]# mkdir /home/nisuser
[root@smallfry tmp]# chmod 700 /home/nisuser/
[root@smallfry tmp]# ll /home
total 2
drwx------ 2 nisuser users 1024 Aug 4 08:05 nisuser
[root@smallfry tmp]#
[root@smallfry tmp]# cp /etc/skel/.* /home/nisuser/
cp: omitting directory `/etc/skel/.'
cp: omitting directory `/etc/skel/..'
cp: omitting directory `/etc/skel/.kde'
[root@smallfry tmp]# chown -R nisuser:users /home/nisuser
[root@smallfry tmp]#
NIS Troubleshooting
Troubleshooting is always required as any part of your daily routine, NIS is no exception. Here are some simple steps to follow to get it working again.
1. The rpcinfo provides a list of TCP ports that your NIS client or server is using. Make sure you can TELNET to these ports from the client to the server and vice versa. If this fails, make sure all the correct NIS daemons are running and that there are no firewalls blocking traffic on the network or on the servers themselves. These ports change from time to time, so memorizing them won't help much.
The example tests from the client to the server.
[root@bigboy tmp]# rpcinfo -p
program vers proto port
100000 2 tcp 111 portmapper
100000 2 udp 111 portmapper
100024 1 udp 32768 status
100024 1 tcp 32768 status
391002 2 tcp 32769 sgi_fam
100009 1 udp 1018 yppasswdd
100004 2 udp 611 ypserv
100004 1 udp 611 ypserv
100004 2 tcp 614 ypserv
100004 1 tcp 614 ypserv
100007 2 udp 855 ypbind
100007 1 udp 855 ypbind
100007 2 tcp 858 ypbind
100007 1 tcp 858 ypbind
600100069 1 udp 874 fypxfrd
600100069 1 tcp 876 fypxfrd
[root@bigboy tmp]#
[root@smallfry tmp]# telnet 192.168.1.100 858
Trying 10.41.32.71...
Connected to 10.41.32.71.
Escape character is '^]'.
^]
telnet> quit
Connection closed.
[root@smallfry tmp]#
2. Always use the ypmatch, getent, and ypwhich commands to check your NIS connectivity. If there is any failure, check your steps over again and you should be able to find the source of your problem.
3. Do not fail to create a user's home directory, set its permissions, and copy the /etc/skel files correctly. If you forget, which is a common error, your users may have incorrect login prompts and no ability to create files in their home directories.
It can never be overemphasized that one of the best places to start troubleshooting is by looking in your error log files in the /var/log directory. You'll save a lot of time and effort if you always refer to them whenever the problem doesn't appear to be obvious.
Conclusion
NIS is a very useful tool for centralized login management, but it has two shortcomings: NIS clients are typically limited to Unix or Linux operating systems, and the password information passes over the network unencrypted.
Newer authentication schemes overcome these issues. For example, LDAP, which is discussed in Chapter 31, "Centralized Logins Using LDAP and RADIUS", provides both encryption and the ability to be used on varied types of equipment. Unfortunately older operating systems don't support it, making NIS the preferred option in some cases.
As always, explore your options when deciding on a centralized login scheme. A wrong decision could haunt you for a long time.
|
Configuring Another Network Installation Server
The Red Hat exams test your knowledge of Linux. The most efficient way to share files between Linux computers is NFS. If you have a choice on the exams, install Red Hat Enterprise Linux over a network connection, using NFS. However, it's possible that you'll want or need to install Red Hat Enterprise Linux using one of the two other available protocols: HTTP or FTP.
HTTP Installation Server
The most popular Web server on the Internet is Apache, which you can easily install with Red Hat Enterprise Linux. The basic steps are the same as for the NFS server. The details are slightly different. I'm assuming that you've already installed the Apache Web server as described in The basic Apache share directory corresponds to the DocumentRoot variable, which is by default the /var/www/html directory. In other words, you'd copy the Red Hat Installation files to a subdirectory of this directory. For the purpose of this chapter, I've created the /var/www/html/test directory. Here are the detailed steps:
- Create a directory for your installation files. With the following command, I'm creating the /var/www/html/test directory. (If you get an error message, Apache may not be properly installed.)
# mkdir /var/www/html/test - Insert the first Red Hat Enterprise Linux installation CD into its drive. Mount it with the following command. (If all you have are the ISO files, say in the /tmp directory, you can mount the first Red Hat Enterprise Linux installation CD with the mount -t iso9660 -ro loop /tmp/firstcd.iso /mnt/cdrom command.)
# mount /mnt/cdrom - Copy the required files from the first Red Hat Enterprise Linux installation CD.
# cp -ar /mnt/cdrom/RedHat /var/www/html/test/ - Copy the .discinfo file from the first Red Hat Enterprise Linux installation CD. This is required if you want to use redhat-config-packages (also known as the Red Hat Package Management tool) to add software using this installation server after Linux is installed. (While there are a number of other files on the first RHEL 3 installation CD, .discinfo is the only file that's absolutely required for an installation server.)
# cp /mnt/cdrom/.discinfo /var/www/html/test/ - Unmount the first Red Hat Enterprise Linux installation CD.
# umount /mnt/cdrom - Repeat steps 2, 3, and 5 with the remaining Red Hat Enterprise Linux installation CDs.
- Make sure there's nothing blocking access to your Apache server. While inelegant, the following command 'flushes,' or turns off the standard Linux firewall from the local computer.
# iptables -F - Now you can activate the Apache service, httpd. The following commands assume that it's already running (which you can check with the service httpd status command):
# service httpd stop # service httpd start
When you install Red Hat Enterprise Linux from an Apache HTTP server, you'll need to remember the directory with the Red Hat installation files. For an HTTP server, the right directory is relative to the DocumentRoot variable, /var/www/html. With these steps, the installation files are in /var/www/html/test; therefore, the correct directory is /test.
FTP Installation Server
One of the oldest protocols still in common use on the Internet is FTP, the File Transfer Protocol. It's efficient, it's easy to use, and now that Red Hat has implemented the very secure FTP (vsFTP) service on its systems, it's relatively secure.
The basic steps are the same as for the NFS server. I'm assuming that you've already installed the vsFTP server, as described in . The basic FTP share directory is /var/ftp/pub. In other words, you'd copy the Red Hat Installation files to a subdirectory of this directory. For the purpose of this chapter, I've created the /var/ftp/pub/test directory. Here are the detailed steps:
- Create a directory for your installation files. With the following command, I'm creating the /var/ftp/pub/test directory. (If you get an error message, Apache may not be properly installed.)
# mkdir /var/ftp/pub/test - Insert the first Red Hat Enterprise Linux installation CD into its drive. Mount it with the following command. (If all you have are the ISO files, say in the /tmp directory, you can mount the first RHEL installation CD with the mount -t iso9660 -ro loop /tmp/firstcd.iso /mnt/cdrom command.)
# mount /mnt/cdrom - Copy the required files from the first Red Hat Enterprise Linux installation CD.
# cp -ar /mnt/cdrom/RedHat /var/ftp/pub/test - Copy the .discinfo file from the first Red Hat Enterprise Linux installation CD. This is required if you want to use redhat-config-packages (also known as the Red Hat Package Management tool) to add software using this installation server after Linux is installed. (While there are a number of other files on the first RHEL 3 installation CD, .discinfo is the only file that's absolutely required for an installation server.)
# cp /mnt/cdrom/.discinfo /var/www/html/test/ - Unmount the first Red Hat Enterprise Linux installation CD.
# umount /mnt/cdrom - Repeat steps 2, 3, and 5 with the remaining Red Hat Enterprise Linux installation CDs.
- Make sure there's nothing blocking access to your Apache server. While inelegant, the following command 'flushes,' or turns off the standard Linux firewall from the local computer.
# iptables -F - Now you can activate the FTP server, vsFTP. The following commands assume that it's already running (which you can check with the service vsftpd status command):
# service vsftpd stop # service vsftpd start
When you install Red Hat Enterprise Linux from an FTP server, you'll need to remember the directory with the Red Hat installation files. For an FTP server, the right directory is relative to the basic /var/ftp directory. With these steps, the installation files are in /var/ftp/pub/test; therefore, the correct directory is /pub/test.
Requirements for Network Installations
Now that you've set up the Red Hat Enterprise Linux installation files on a network server, let's look at what else you'll need on the computer where you'll be installing Linux. Once Linux detects your network card, you'll need to configure that card to be a part of your network. It'll be done by a DHCP (Dynamic Host Configuration Protocol) server or by static IP addressing.
| Exam Watch |
A DHCP server is based on the Dynamic Host Configuration Protocol. If you're going to install RHEL over a network during the exam, your proctor will tell you that there's an DHCP server for your network, or should give you the static IP address information that you'll use.
|
If there's a DHCP server for your network, this process is easy. All you'll need to do is set the Linux installation program to ask for your IP address information from that DHCP server. As long as there are no active firewalls between your computer and the DHCP server, you should not have any problems.
Otherwise, you'll need to configure your computer with static IP addresses. In this case, you'll need a valid, unused IP address, the local network mask, the default gateway IP address (if the installation files are on a different LAN), and optionally, the primary DNS IP address, a domain name such as example.com, and the hostname to use for the local computer.
As you can see in Figure 2-2, Anaconda allows you to get your IP address information from a DHCP server or enter the static IP address information yourself.
Configuring a Network Installation
Most Linux users can install Red Hat Enterprise Linux from a CD-ROM. During the installation portion of the Red Hat exam, you'll probably want to save time by installing RHEL 3 over a network on an NFS, HTTP, or FTP server. As you'll want to practice network installations, you'll want to set up a network server. For completeness, you can also install RHEL from ISO images on a local hard disk.
Configuring a Network Installation Server
Once you have the Red Hat installation CDs, configuring a network installation server is a fairly easy process. All you need to do is copy the files from each CD's /RedHat directory to a common directory, configure sharing on the directory, and then activate the NFS, FTP, or HTTP network.
Before you set up a network installation source, you'll need a partition with about 2GB of free space (or more). I'll illustrate the process for an NFS server, and explain the variations for FTP and HTTP servers.
Creating an NFS Installation Server
In the following steps, I'll show you how to create a shared directory, copy the Red Hat installation files, and then set up the share through NFS. As NFS is the most efficient way to share files between Linux and Unix computers, I think it's the most likely option for network installations during the exam. You'll need the Red Hat Enterprise Linux installation CDs, or at least the ISO files associated with those CDs.
- Create a directory for your installation files. With the following command, I can create the /mnt/inst directory:
# mkdir /mnt/inst - Insert the first Red Hat Enterprise Linux installation CD into its drive. Mount it with the following command. (If all you have are the ISO files, say in the /tmp directory, substitute mount -t iso9660 -ro loop /tmp/firstcd.iso /mnt/cdrom.)
# mount /mnt/cdrom - Copy the required files from the first Red Hat Enterprise Linux installation CD.
# cp -ar /mnt/cdrom/RedHat /mnt/inst - Copy the .discinfo file from the first Red Hat Enterprise Linux installation CD. This is required if you want to use redhat-config-packages (also known as the Red Hat Package Management tool) to add software using this installation server after Linux is installed. (While there are a number of other files on the first RHEL 3 installation CD, .discinfo is the only file that's absolutely required for an installation server.)
# cp /mnt/cdrom/.discinfo /mnt/inst - Unmount the first Red Hat Enterprise Linux installation CD.
# umount /mnt/cdrom - Set up an NFS share. Add the following line to /etc/exports. You can do it with a text editor such as vi or the redhat-config-nfs utility (also known as the NFS Server Configuration tool)
/mnt/inst *(ro,sync) - Export the shared directory.
# exportfs -a - Make sure there's nothing blocking access to NFS. The default Red Hat Enterprise Linux firewall blocks access to an NFS server. While inelegant, the following command 'flushes,' or turns off the standard Linux firewall from the local computer.
# iptables -F - Now you can activate the NFS service. The following commands assume that it's already running (which you can check with the service nfs status command):
# service nfs stop # service nfs start - Finally, you can check the status of your share. If it's working, you should see the contents of the /etc/exports directory when you run the following command:
# showmount -e
When you install Red Hat Enterprise Linux from an NFS server, you'll need the name of the installation directory, in this case, /mnt/inst.
| On The Job |
For an NFS connection, you don't need to copy the files from a CD. If you've downloaded ISOs of the RHEL installation CDs, all you need to do is copy them to the shared NFS directory, in this case, /mnt/inst. However, this does not work for FTP or HTTP servers.
|
Configuring Another Network Installation Server
The Red Hat exams test your knowledge of Linux. The most efficient way to share files between Linux computers is NFS. If you have a choice on the exams, install Red Hat Enterprise Linux over a network connection, using NFS. However, it's possible that you'll want or need to install Red Hat Enterprise Linux using one of the two other available protocols: HTTP or FTP.
HTTP Installation Server
The most popular Web server on the Internet is Apache, which you can easily install with Red Hat Enterprise Linux. The basic steps are the same as for the NFS server. The details are slightly different. I'm assuming that you've already installed the Apache Web server as described in Chapter 7. The basic Apache share directory corresponds to the DocumentRoot variable, which is by default the /var/www/html directory. In other words, you'd copy the Red Hat Installation files to a subdirectory of this directory. For the purpose of this chapter, I've created the /var/www/html/test directory. Here are the detailed steps:
- Create a directory for your installation files. With the following command, I'm creating the /var/www/html/test directory. (If you get an error message, Apache may not be properly installed.)
# mkdir /var/www/html/test - Insert the first Red Hat Enterprise Linux installation CD into its drive. Mount it with the following command. (If all you have are the ISO files, say in the /tmp directory, you can mount the first Red Hat Enterprise Linux installation CD with the mount -t iso9660 -ro loop /tmp/firstcd.iso /mnt/cdrom command.)
# mount /mnt/cdrom - Copy the required files from the first Red Hat Enterprise Linux installation CD.
# cp -ar /mnt/cdrom/RedHat /var/www/html/test/ - Copy the .discinfo file from the first Red Hat Enterprise Linux installation CD. This is required if you want to use redhat-config-packages (also known as the Red Hat Package Management tool) to add software using this installation server after Linux is installed. (While there are a number of other files on the first RHEL 3 installation CD, .discinfo is the only file that's absolutely required for an installation server.)
# cp /mnt/cdrom/.discinfo /var/www/html/test/ - Unmount the first Red Hat Enterprise Linux installation CD.
# umount /mnt/cdrom - Repeat steps 2, 3, and 5 with the remaining Red Hat Enterprise Linux installation CDs.
- Make sure there's nothing blocking access to your Apache server. While inelegant, the following command 'flushes,' or turns off the standard Linux firewall from the local computer.
- Now you can activate the Apache service, httpd. The following commands assume that it's already running (which you can check with the service httpd status command):
# service httpd stop # service httpd start
When you install Red Hat Enterprise Linux from an Apache HTTP server, you'll need to remember the directory with the Red Hat installation files. For an HTTP server, the right directory is relative to the DocumentRoot variable, /var/www/html. With these steps, the installation files are in /var/www/html/test; therefore, the correct directory is /test.
FTP Installation Server
One of the oldest protocols still in common use on the Internet is FTP, the File Transfer Protocol. It's efficient, it's easy to use, and now that Red Hat has implemented the very secure FTP (vsFTP) service on its systems, it's relatively secure.
The basic steps are the same as for the NFS server. I'm assuming that you've already installed the vsFTP server, as described in Chapter 7. The basic FTP share directory is /var/ftp/pub. In other words, you'd copy the Red Hat Installation files to a subdirectory of this directory. For the purpose of this chapter, I've created the /var/ftp/pub/test directory. Here are the detailed steps:
- Create a directory for your installation files. With the following command, I'm creating the /var/ftp/pub/test directory. (If you get an error message, Apache may not be properly installed.)
# mkdir /var/ftp/pub/test - Insert the first Red Hat Enterprise Linux installation CD into its drive. Mount it with the following command. (If all you have are the ISO files, say in the /tmp directory, you can mount the first RHEL installation CD with the mount -t iso9660 -ro loop /tmp/firstcd.iso /mnt/cdrom command.)
# mount /mnt/cdrom - Copy the required files from the first Red Hat Enterprise Linux installation CD.
# cp -ar /mnt/cdrom/RedHat /var/ftp/pub/test - Copy the .discinfo file from the first Red Hat Enterprise Linux installation CD. This is required if you want to use redhat-config-packages (also known as the Red Hat Package Management tool) to add software using this installation server after Linux is installed. (While there are a number of other files on the first RHEL 3 installation CD, .discinfo is the only file that's absolutely required for an installation server.)
# cp /mnt/cdrom/.discinfo /var/www/html/test/ - Unmount the first Red Hat Enterprise Linux installation CD.
# umount /mnt/cdrom - Repeat steps 2, 3, and 5 with the remaining Red Hat Enterprise Linux installation CDs.
- Make sure there's nothing blocking access to your Apache server. While inelegant, the following command 'flushes,' or turns off the standard Linux firewall from the local computer.
# iptables -F - Now you can activate the FTP server, vsFTP. The following commands assume that it's already running (which you can check with the service vsftpd status command):
# service vsftpd stop # service vsftpd start
When you install Red Hat Enterprise Linux from an FTP server, you'll need to remember the directory with the Red Hat installation files. For an FTP server, the right directory is relative to the basic /var/ftp directory. With these steps, the installation files are in /var/ftp/pub/test; therefore, the correct directory is /pub/test.
Requirements for Network Installations
Now that you've set up the Red Hat Enterprise Linux installation files on a network server, let's look at what else you'll need on the computer where you'll be installing Linux. Once Linux detects your network card, you'll need to configure that card to be a part of your network. It'll be done by a DHCP (Dynamic Host Configuration Protocol) server or by static IP addressing.
| Exam Watch |
A DHCP server is based on the Dynamic Host Configuration Protocol. If you're going to install RHEL over a network during the exam, your proctor will tell you that there's an DHCP server for your network, or should give you the static IP address information that you'll use.
|
If there's a DHCP server for your network, this process is easy. All you'll need to do is set the Linux installation program to ask for your IP address information from that DHCP server. As long as there are no active firewalls between your computer and the DHCP server, you should not have any problems.
Otherwise, you'll need to configure your computer with static IP addresses. In this case, you'll need a valid, unused IP address, the local network mask, the default gateway IP address (if the installation files are on a different LAN), and optionally, the primary DNS IP address, a domain name such as example.com, and the hostname to use for the local computer.
Anaconda allows you to get your IP address information from a DHCP server or enter the static IP address information yourself.
You'll also need the hostname or IP address of the Red Hat Enterprise Linux installation server. If you have the hostname, you'll also need the IP address of the DNS server for the network used for the exam. As shown in , this is also known as the Primary nameserver. If the DNS server is not on the LAN, you'll also need the Default gateway IP address.
| On The Job |
If you're installing Red Hat Enterprise Linux from files on a network server, check the firewall on that server. The standard RHEL 3 and Red Hat Linux 9 firewalls cut off network communication to whatever FTP, HTTP, or NFS server you might be using to store the /RedHat directory tree.
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You'll also need the hostname or IP address of the Red Hat Enterprise Linux installation server. If you have the hostname, you'll also need the IP address of the DNS server for the network used for the exam. this is also known as the Primary nameserver. If the DNS server is not on the LAN, you'll also need the Default gateway IP address.
| On The Job |
If you're installing Red Hat Enterprise Linux from files on a network server, check the firewall on that server. The standard RHEL 3 and Red Hat Linux 9 firewalls cut off network communication to whatever FTP, HTTP, or NFS server you might be using to store the /RedHat directory tree.
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