How do I allow external users to relay mail through my server?

Question

How I can setup my GMS server to allow outside users to
relay their mail through my server. I only want to allow users from my domain to do this, I don’t want to open this up to everyone on the Internet.

I have some sales people that travel and they need to both send and receive mail on the road. I have set them up to POP their mail but they cannot send mail back through my system. What can I do?

Answer

There are 3 options that you should be looking at.

Version 18 or above

1. Local IP – It is possible to allow a single IP address or a range of IP addresses to be classed as local. Any user connecting from within this range is then allowed to relay. This option is configured under the System Administration > Security > Local IP. This should only really be used with static IP addresses for obvious reaons.
2. Authenticated SMTP – Enable "Allow AUTH login" and the subsequent authentication mechanisms from under System Administration > Performance > ESMTP page. Your remote users will then have to authenticate to the SMTP service when sending external messages through your server. The drawback is that this is only supported by some mail clients.
3. POP-before-SMTP and IMAP-before-SMTP – this requires that you have a GMS Anti-Spam key but does have an advantage of being supported by all mail clients. These options are enabled and controlled under the system Anti-Spam > Bypasses > Authenticated Clients page of the GMS Administrative interface

Version 17 or below

1. Local IP – It is possible to allow a single IP address or a range of IP addresses to be classed as local. Any user connecting from within this range is then allowed to relay. This option is configured under the Security > Local IP. This should only really be used with static IP addresses for obvious reaons.
2. Authenticated SMTP – Enable "Allow AUTH login" and the subsequent authentication mechanisms from under Mail > Incoming > ESMTP page. Your remote users will then have to authenticate to the SMTP service when sending external messages through your server. The drawback is that this is only supported by some mail clients.
3. POP-before-SMTP and IMAP-before-SMTP – this requires that you have a GMS Anti-Spam key but does have an advantage of being supported by all mail clients. These options are enabled and controlled under the system Anti-Spam > Bypasses > Authenticated Clients page of the GMS Administrative interface

See Also:

• What is IMAP before SMTP?
• How do I use SMTP Authentication with Netscape or Outlook Express?
• Attempts to use SMTP authentication with Eudora Version 5 fail
• What is POP before SMTP?
• How do I prevent Gordano Products acting as an open relay?
• How do I enable SMTP Authentication?

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