I have a small farm with SP2010 (2 backends and 2 frontends). My SMTP is protected by a firewall, and my question is if I must to open for port 25 in the rules of firewall only one ip, where the Central Administration is installed or I must open the port 25 for all servers in the farm because all of them can to send an outgoing email. If the outgoing email resides only in one server (Central Administration), may I have redundancy with outgoing email? Thanks in advance. Tonio
I would advise opening the port for all servers to allow the timer job to run on any server if another server is unavailable.
This could be part of a disaster recovery or availability plan.