Setting up networking on a new computer (Linux)

Windows

Note: see windows_networking.html for info on windows networking

The GNOME/RedHat GUI way

Use the following GUI tools to setup networking. Setting up networking with an ethernet cable is easiest. Even with PCMCIA cards RedHat Linux seems to be able to set up networking with the default kernel.

system-config-network - configure network connections
system-control-network - configure network connections
gnome-nettool - diagnostic tool for networking

The commandline way

There are a bunch of command line programs for setting up networking

netloc - Acorn's utility for setting up wired and wireless connections
modprobe - use this to insert a module for your hardware into the kernel
ifconfig - configure IP addresses, netmasks, etc
iwconfig - wireless settings for an 802.11[abg] radio card.

Type "ifconfig" to get a list of network interfaces. The "lo" interface is the loopback interface (not useful for connecting to the internet). If you see "eth0" or "eth1" or something that looks like it might be a wireless interface then the kernel part is set up and you just need to configure the IP address, netmask, etc. For that look at 'man ifconfig' and 'man dhclient.conf' man pages.

If you do not see any "eth0" or "eth1" etc interfaces when you type 'ifconfig' then the module for your hardware is not loaded. You can try using the GUI methods above. Also try

'lspci -v' for pci devices
'lsusb' for usb devices
'cardctl' for pcmcia devices

See the man pages for more info.

Modifying the files

Here are the files affected (this is on Redhat and maybe other systems):

/etc/sysconfig/network
/etc/sysconfig/network-scripts/ifcfg-eth0 or
/etc/sysconfig/networking/devices/ifcfg-eth0
/etc/resolv.conf

After updating files type

    sudo ifdown eth0
    sudo ifup eth0

DHCP setup

ifcfg-eth0

DEVICE=eth0
BOOTPROTO=dhcp
ONBOOT=yes
DHCP_HOSTNAME=<hostname>
USERCTL=no
PEERDNS=yes
TYPE=Ethernet

network

NETWORKING=yes
HOSTNAME=<hostname.domain>

resolv.conf

(DHCP should generate this file)

Static IP setup

ifcfg-eth0

DEVICE=eth0
BOOTPROTO=none
ONBOOT=yes
USERCTL=no
TYPE=Ethernet
IPADDR=<IP-addr>
NETMASK=<netmask>
BROADCAST=<broadcast>
NETWORK=<network>

ifcfg-eth0 (alternate version)

DEVICE=eth0
BOOTPROTO=none
ONBOOT=yes
USERCTL=no
TYPE=Ethernet
IPADDR=<IP-addr>
NETMASK=<netmask>
BROADCAST=
NETWORK=

network

NETWORKING=yes
HOSTNAME=<hostname.domain>
GATEWAY=<gateway-IP-addr>
GATEWAYDEV=eth0

resolv.conf

search <domain1> <domain2> <domain3> ...
nameserver <nameserver-IP-addr>
nameserver <optional-nameserver2-IP-addr>
...

Inserting modules

You may have to insert modules to get networking to work. If you type 'ifconfig' and do not see 'eth0' or 'eth1'... then the module is probably not loaded. Try one of these:

modprobe 3c59x          # ethernet
modprobe yenta_socket   # PCMCIA cards
modprobe prism54        # wireless PRISM cards