Solaris basics: configuring ethernet interfaces

Recently I’ve had several clients who’ve just started with Solaris, and who have had roughly similar questions. So I thought I’d put up a few “How To” posts covering some Solaris basics.

Each LAN interface in Solaris has a configuration file in /etc which is named after the interface name and it’s instance.

So, let’s assume that you have two e1000g interfaces configured – you’d have two configuration files:

/etc/hostname.e1000g0
/etc/hostname.e1000g1

These files will just contain a hostname, which maps to an entry in /etc/hosts.

An example from my OpenSolaris development workstation:

bash-3.2$ cat /etc/hostname.e1000g0 
grond 

And this is /etc/hosts:

# Internet host table 
# 
::1 grond grond.local localhost loghost 
127.0.0.1 localhost 
192.168.13.100	grond grond.local loghost 

When Solaris boots, all it does to configure a LAN interface is look for hostname.* files in /etc. It then looks up the hostname in /etc/hosts to find out the IP address, then configures the interface.

So if you need to change the IP address of a LAN interface in Solaris, all you need to do is edit the hostname entry in /etc/hosts and reboot. For example, to change grond’s e1000g0 IP address to a different subnet, /etc/hosts would be modified to:

# Internet host table 
# 
::1 grond grond.local localhost loghost 
127.0.0.1 localhost 
192.168.125.100	grond grond.local loghost 

Then reboot the host for the changes to take effect.