14.4. Network Integration

Currently TCP/IP is the standard network protocol by which all modern operating systems can communicate. Nevertheless, Linux also supports other network protocols, such as the IPX protocol (formerly) used by Novell Netware or the Appletalk protocol used by Macintosh machines. This chapter merely focuses on the integration of a Linux host in a TCP/IP network. To integrate arcnet, token ring, or FDDI network cards, refer to the kernel source documentation in /usr/src/linux/Documentation (package kernel-source).

14.4.1. Requirements

The machine must have a supported network card. Normally, the network card is detected during the installation and a suitable driver is loaded. To see if your card has been integrated correctly with the appropriate driver, enter the command ifstatus eth0. The output should show the network device eth0.

If the kernel support for the network card is implemented as a module, which is done by default for the SUSE kernel, the name of the module must be entered as an alias in /etc/modules.conf. For example, the entry for the first ethernet card could be alias eth0 tulip. This is done automatically when the driver support for the network card is loaded in linuxrc during the first installation. This task can also be done after installation with YaST.

If you are using a hotplug network card (e.g., PCMCIA or USB), the drivers are autodetected when the card is plugged in. No configuration is necessary.

14.4.2. Configuration with YaST

To configure the network card with YaST, start the Control Center and select Network Devices -> Network Card Configuration. With Add, configure a new network card. With Delete, remove it from the configuration. With Edit, modify the network card configuration.

Activate Advanced Settings->Hardware Details to modify the hardware data for an already configured network card with Edit. This opens the dialog for changing the settings of the network card, shown in Figure 14.3. “Configuring the Hardware Parameters”.

Normally, the correct driver for your network card is configured during installation and is activated. Therefore, manual hardware configuration is only needed if multiple network cards are used or if the network hardware is not automatically recognized. In this case, select Add to specify a new driver module.

Figure 14.3. Configuring the Hardware Parameters

Configuring the Hardware Parameters

In this dialog, set the network card type and, for an ISA card, the interrupt to implement and the I/O port. For some network drivers, also specify special parameters, such as the interface to use or whether it uses an RJ-45 or a BNC connection. For this, refer to the driver module documentation. To use PCMCIA or USB, activate the respective check boxes.

After entering the hardware parameters, configure additional network interface data. Select Interface in the Network Base Configuration to activate the network card and assign it an IP address. Select the card number then click Edit. A new dialog appears in which to specify the IP address and other IP network data. Find information about assigning addresses to your own network in Section 14.1. “TCP/IP — The Protocol Used by Linux” and Table 14.3. “Private IP Address Domains”. Otherwise, enter the address assigned by your network administrator in the designated fields.

Configure a name server under Host Name and Name Server so the name resolution functions as described in Section 14.6. “DNS — Domain Name System”. Via Routing, set up the routing. Select Configuration for Experts to make advanced settings.

If you are using wireless LAN cards, activate Wireless Device. Important settings, such as the operation mode, network names, and the key for encrypted data transfer, can be made in a special dialog.

With that, the network configuration is complete. YaST starts SuSEconfig and transfers the settings to the corresponding files (see Section 14.3. “Manual Network Configuration”). For the changes to take effect, the relevant programs must be reconfigured and the required daemons must be restarted. Do this by entering rcnetwork restart.

14.4.3. Hotplug and PCMCIA

Hotplug network cards, like PCMCIA or USB devices, are managed in a somewhat special way. Normal network cards are fixed components assigned a permanent device name, such as eth0. By contrast, PCMCIA cards are assigned a free device name dynamically on an as-needed basis. To avoid conflicts with fixed network cards, hotplug and PCMCIA services are loaded after the network has been started.

PCMCIA-related configuration and start scripts are located in the directory /etc/sysconfig/pcmcia. The scripts are executed as soon as cardmgr, the PCMCIA device manager, detects a newly inserted PCMCIA card — which is why PCMCIA services do not need to be started before the network during boot.

14.4.4. Configuring IPv6

To configure IPv6, you will not normally need to make any changes on the individual workstations. However, IPv6 support must be loaded. To do this, enter modprobe ipv6 as root.

Because of the autoconfiguration concept of IPv6, the network card is assigned an address in the link-local network. Normally, no routing table management takes place on a workstation. The network routers can be queried by the workstation, using the router advertisement protocol, for what prefix and gateways should be implemented. The radvd program can be used to set up an IPv6 router. This program informs the workstations which prefix to use for the IPv6 addresses and which routers. Alternatively, use zebra for automatic configuration of both addresses and routing.

Consult the manual page of ifup (man ifup) to get information about how to set up various types of tunnels using the /etc/sysconfig/network files.