There is already a similar thread in the normal forum (http://www.iredmail.org/forum/topic836-transports.html) - but I think this topic is more related to the pro version.

We want to relay whole domains to external smtp servers (relay setting in admin tool e.g. smtp:[10.0.0.1]:25

But this does not work.. see also my posting there..

Any ideas how to fix this without manual ldap entries?

Regards