I'm going to give an example of configuring a GigaSwift network interface card in a Sun Blade workstation. For this example, you will have to reboot your box, but you can configure the card online, too.
# vi /etc/hosts
127.0.0.1 localhost
168.123.xxx.xxx esofthub (my workstation's hostname)
:wq! (save and quit)
# vi /etc/hostname.ce0
esofthub (should be the hostname of your workstation)
:wq! (save and quit)
# vi /etc/netmasks
168.123.xxx.xxx 255.255.255.xxx
:wq! (save and quit)
# init 6 (reboots your workstation)