Topic: mail from some domains not delivering

[KevinM]

Hi all

I have an unusual problem with one of my clients SME mail boxes (V6.0.1, with updates, but essentially an out of box install). It is configured with four of the clients domains added and receives mail fine from all around the world, well almost. They have two clients who cannot get email to deliver if the box (on a static ip) is set as the primary MX. If I change and make my main mail server the primary MX (then they pull down with fetchmail) it delivers fine.

I know one of the the problem clients has an MS/Windows box for their gateway running MDaemon ver 5.0.7. Does anyone know if MDaemon gives up when the email response is 'too long', ie the mailfront does its thing but takes about 30 seconds or so to respond with the SMTP banner.

Regards
Kevin

[Anonymous]

Hi all
 They have two clients who cannot get email to deliver if the box (on a static ip) is set as the primary MX. If I change and make my main mail server the primary MX (then they pull down with fetchmail) it delivers fine.

Sounds like ISP is blocking inbound port 25, but outbound POP is OK.

[Anonymous]

Can't see that is the problem. They are on a telstra static ip so they can deliver fine, the problem is just two of many remote clients sending to them.

If I set the mail to deliver to my primary sendmail based mail server all is fine. However, if I reset the dns with primary MX pointing at the SME server then at least these two remote users are unable to send to the machine. (Later after I set the dns/primary MX back to my server the queued problem email arrived ok.)

Currently left on my primary sendmail server and would rather it wasn't....

Regards
kevin

[smeghead]

Check the Sendmail logs on you primary and look at the conversation between the 2 mail servers; compare to the logs on the SME box.  It might be trying to verify the connection is some arcane way?  It might trying to authenticate in some arcane way?