Apple Mac OS X Server (Administrator’s Guide) - Manual (Page 391)

Mail Service 391
Changing the Incoming SMTP Port Number
You can change the port number on which your SMTP service receives incoming mail from
other servers. Other servers must use this port number to deliver incoming mail to your
server. The standard incoming SMTP port is 25. You can change this port number, but do so
carefully. If you change to a nonstandard incoming SMTP port number, other servers will be
unable to deliver incoming mail to your server unless they use this nonstandard port number
for their outgoing SMTP mail. Make sure you don’t change to a port number already in use by
other services or operations.
To change the incoming SMTP port number:
1 In Server Settings, click the Internet tab.
2 Click Mail Service and choose Configure Mail Service.
3 Click the Protocols tab and select Enable SMTP, if it is not already checked.
4 Change the port number for the SMTP protocol and click Save.
Changing the Outgoing SMTP Port Number
You can change the port number that your SMTP service uses when attempting to send
outgoing mail to other servers. The standard port for outgoing SMTP connections is 25. You
can change this port number, but do so carefully. If you use a nonstandard outgoing SMTP
port, your server will be unable to deliver outgoing mail to other servers unless they use this
nonstandard port for their incoming SMTP mail. Make sure you don’t change to a port
number already in use by another service or operation.
To change the outgoing SMTP port number:
1 In Server Settings, click the Internet tab.
2 Click Mail Service and choose Configure Host Settings.
3 Click the Network Settings tab.
4 Change the SMTP port number and click Save.
Enabling an Alternate Mail Transfer Agent
You can use an alternate mail transfer agent, such as the UNIX Sendmail program, to handle
incoming and outgoing SMTP mail. Any mail sent to local email users is processed by the mail
transfer agent and transferred to the Mac OS X Server mail service for delivery. POP and
IMAP continue to function as usual, but SMTP mail is now subject to the rules and settings of
the mail transfer agent.
To use another mail transfer agent:
1 In Server Settings, click the Internet tab.
2 Click Mail Service and choose Configure Mail Service.