The procedure for changing hostname varies, depending of the Solaris version:

SOLARIS 11

1. Change the nodename/config property in system/identity:node service:

# svccfg -s system/identity:node setprop config/nodename="new_hostname"

2. Refresh the configuration and restart the system/identity:node service

# svcadm refresh system/identity:node
# svcadm restart system/identity:node

3. Edit /etc/hosts and modify the hostname

SOLARIS 10

1. Modify the host name in the following files:

/etc/hosts
/etc/nodename
/etc/hostname.<interface>

<interface> is the name of the primary network interface

2. Reboot the system

# init 6

SOLARIS 9 AND BELOW

1. Modify the host name in the following files:

/etc/hosts
/etc/nodename
/etc/hostname.<interface>
/etc/net/ticlts/hosts
/etc/net/ticots/hosts
/etc/net/ticotsord/hosts

<interface> is the name of the primary network interface

2. Reboot the system

# init 6