Ports
From Kb
SMTP
Some ISP's block SMTP relaying as a security precaution. This means that you can either use their SMTP server or try a different port.
The normal SMTP port on servers is 25. This is also the port that many ISP's block. On my servers there are 3 available ports for SMTP:
Available SMTP ports
- 25 (Old standard)
- 587 (Fairly recent new standard, see RFC 2476)
- 5190 (Alternate port)
IMAP
- 143
Google Apps
If the standard port (465) is not working, try using 587. You can also try using their alternate mail server "smtp.googlemail.com".