Configuration of Network Devices

All previous discussion on internetworking has assumed that our computers have been 'up and running', and possessed full knowledge about their networking environment. Where did this knowledge come from?

The standard booting sequence for most operating systems involves the computer's hard-disk (or CD-ROM, flash-memory, ...) providing a short bootstrap program of several hundred bytes, which in turn reads the true operating system code from nominated blocks on permanent media. To configure its network connection, a client host requires (at least):

• one unique IP address for each of its network interfaces,
• the client's hostname
• the address of its default router - where to send all packets that we don't explicitly know how to deliver,
• each interface's subnet mask to determine how many bits of the IP address provide the network and host ids,
• the IP address of an initial domain name server, to resolve host names to their IP addresses,
• (maybe) the time, or at least timezone.

A reasonable first approach to defining this information is in a configuration file (see our labs' /etc/sysconfig/network*):

    DEVICE=eth0
    BROADCAST=130.95.1.255
    NETMASK=255.255.255.0
    IPADDR=130.95.1.8
    BOOTPROTO=none
    GATEWAY=130.95.1.41
    GATEWAYDEV=eth0
    HOSTNAME=budgie.csse.uwa.edu.au