> if my users execute command : mail nick , mail is
> not relayed and put in /var/spool/mail
>
Hello Demian,

I think you must define:

mydestination =

in your main.cf so postfix never will be deliver local.
Otherwise you can define a spezial transport methode for your domain with:

foo.com
smtp:smtp2.foo.com
..foo.com
smtp:smtp2.foo.com


in your transport table.

Ihope that will help you


Mike