Troubleshooting a Network Installation

If you re unable to install Red Hat Linux over a network, there are a number of things that you can check. First, most network problems are physical. Red Hat Linux installs a firewall by default, and that firewall may also cause problems. If you don t have correct address settings, your computer won t be able to find the installation server. Finally, there are special issues related to network installations of Red Hat Linux on a laptop.

Checking the Messages

When you re having a problem with a network installation of Red Hat Linux, the problem may not even be with the network. Several text installation screens can provide valuable messages. You can get to these screens with the Ctrl+Alt+F n command, where n is a number between 2 and 5. I ve described these screens in Table 4.9.

Table 4.9: Red Hat Installation Screens

Screen	Description
Ctrl+Alt+F1	Returns to the main installation screen.
Ctrl+Alt+F2	Opens a bash shell with limited command capabilities; for example, the df command can show mounted directories and partitions. Other bash commands are described in Part II of this book.
Ctrl+Alt+F3	Views the installation log, with messages related to hardware detection; if you re having trouble reading CDs or loading drivers, check here.
Ctrl+Alt+F4	Goes to the system message log, with messages such as formatting and mounting directories on partitions.
Ctrl+Alt+F5	Notes various messages such as filesystem labels, blocks, formats, and journals.

Checking the Network

Again, most network problems are physical. When you have a condition where your network is not working, that inevitably means you end up checking your cables, connections, and other hardware components .

There are a number of commands that you can use to test physical connections as well. For example, when you use the ping command on the IP address of another computer, you re testing the connectivity between your computers. Basic network troubleshooting techniques are described in Chapter 21 .

The Firewall on the Server

Red Hat Linux installs a firewall by default. However, if you accept the default installation, you won t be able to access installation files from that computer, at least using the network protocols (NFS, HTTP, and FTP) discussed in this chapter. If you re still having network problems, it s worth logging into and checking the server computer with the Red Hat Linux installation files.

If that server is also running Red Hat Linux 7.3 and above, there are a couple of simple commands that you can use to check for a firewall:

 # iptables -L 

This iptables command lists any current rules that apply to that computer. If there are existing rules, you can "flush" them from the current configuration with the following command:

 # iptables -F 

When the installation is complete, you can reenable the firewall with the service iptables restart command. Firewalls are covered in more detail in Chapter 22 .

Address Settings

Users who are less familiar with IP addressing may make mistakes. For example, if you ve set a static IP address for your computer, you need to make sure that you have several things right:

• The IP address of the computer should be on the same network as your LAN.

• The network mask (or subnet mask) of the computer should match that of every other computer on the LAN.

While it s useful to have the correct default gateway and DNS server IP addresses, those aren t absolutely necessary for a successful network installation of Red Hat Linux. For more information on how IP addressing works, see Chapter 20 .

A Laptop Installation over a Network

Installing Red Hat Linux on a laptop computer is usually trouble-free. However, there are some differences from the standard network installation. Laptop network cards are generally located in a PC Card slot (also known as PCMCIA, based on the standards of the Personal Computer Memory Card International Association).

PC Cards require their own drivers, loaded from a driver disk created from the pcmciadd.img file. As we discussed earlier in this chapter, driver image files are located on the first Red Hat Linux installation CD, in the /images directory.

Many PCMCIA network cards are available; the files in the Red Hat driver disk may not always cover what you need. For example, you need drivers for both the PCMCIA slot and the PCMCIA network card. If you re having problems, open the installation log screen with the Ctrl+Alt+F3 command. You may be able to identify your problem here.