Multiple IP Address on a Solaris System

I needed to assign a second IP address to a network interface on a Solaris 2.7 system. The system has 2 network cards, designated hme0 and hme1, each with its own IP address, but I needed to assign a second IP address to the hme0 interface. A webserver, which would normally be at the second IP address, was down and I wanted the webserver on this particular system to assume the functions of the offline system temporarily by responding at the IP address of the server that was down. In order to have a Solaris 2.x system listen on a second IP address on an interface, the following steps can be taken.

1. Create an entry in /etc/hosts for the second hostname. In this particular case I added a myhost2 entry, so that I had the following entries in the file.

   127.0.0.1    localhost       
   10.0.74.214  myhost1.example.com myhost1   loghost
   10.0.74.193  myhost2.example.com myhost2
   192.168.1.1  janus

   Myhost1 and myhost2 will apply to the same network interface, whereas janus is for the second network interface card in the system. The myhost2 entry is the only new entry.
2. Create /etc/hostname.hme:n files, or /etc/hostname.le0:n files depending on your system configuration, that contain the hostname for the virtual host n. You don't need to create hostname.hme0:0 as it is the same as hostname.hme0.

The above changes will cause the virtual hosts to be configured at boot time. If you don't want to reboot the system, you can use the ifconfig command to have the system start responding on the second IP address without rebooting.

# ifconfig hme0:1 up
# ifconfig hme0:1 128.183.72.193 netmask 255.255.255.0

References:

1. FAQs document :How to setup multiple ip for Solaris
   Date: March 30, 1998
   Freelab
2. Configuring Networking
   By: Keith Parkansky
   Date: May 1, 2002
   Solaris x86

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