The discussion has gone into a different direction - than the one I was looking for. So, I'll rephrase the questions. **** 1 ****** pine -> postfix -> smtp-relay1/smtp-relay2 -> destination When on network-1 I would like to use smtp-relay1 for all outgoing mail When on network-2 I would like to use smtp-relay2 for all outgoing mail I swith between network 1 & 2 twice a day. Note: smtp-relay1, smtp-relay2 are open relays as long as the machine is on the local network - and inaccessiable from outside the local-network. How do I set up postfix configuration to do this - without having to change postfix settings - each time I change networks? **** 2 ******* pine -> postfix -> smtp-relay1 --> destination [for *@aol if machine on network-1] pine -> postfix -> smtp-relay2 --> destination [for *@aol if machine on network-2] pine -> postfix -----------------> destination [for everything else] How do I configure postfix to handle this? **** ******** Thanks. Satish