Change IP Address on Solaris

/etc/hosts, here you have to put the ip and the name.

/etc/hostname.eri0, here the interface file, it varies

/etc/defaultrouter, your new gateway
/etc/defaultdomain, if you will change of domain.
/etc/nodename, you host name

you have to change the mask with ifconfig:
ifconfig eri0 down
ifconfig eri0 a.b.c.d netmask 255.255.255.XXX
ifconfig eri0 up

then you have to restart the server