If your solaris system has a static address assigned to it and you wish to change it, simply update the files corresponding to your version of Solaris as explained below.
Solaris 9 and below change the IP in following file
Solaris 10 till update 3
Solaris 10 update 4 and later
In case you also want to change your gateway, change the router address in…
Also ensure that you have the correct netmask mentioned in the file…
Create the netmasks file if it does not exist.