Source NAT on Solaris 10 5/08 quick how-to
Enable ipv4 forwarding:
routeadm -u -e ipv4-forwarding
Configure NAT in /etc/ipf/ipnat.conf (replace e1000g0 with your outside interface, 172.16.0.0/12 with your LAN IP range):
map e1000g0 172.16.0.0/12 -> 0/32 proxy port ftp ftp/tcp
map e1000g0 172.16.0.0/12 -> 0/32 portmap tcp/udp auto
map e1000g0 172.16.0.0/12 -> 0/32
Enable ipf:
svcadm enable network/ipfilter