sophie on a fail-over environment, what port Sophie runs on, how Sophie fails over to another server.

Hello everyone,

I am building a symmetric fail-over mail system.
When sophie from one system fails to the other system,
I need both sophie sessions to perform on the same server.

Question is: what port Sophie is working on ?
Can I specify a different port for each sophie, 
which configuration file I need to modify
so that when it fails over, its port will not collide.

Any shared experience is appreciated.

Regards,

Paul Tran