Force sendmail to connect to itself....

[peter.m...@gmail.com]

Hi Folks,

Is there a way to do this ? Long story short we use sendmail to deliver all messages to a third party product which adds a header and resubmits the message back to sendmail which then routes the message based on that header. This has worked fine until now because the third part product dropped the initial 250 banner response line thus sendmail was not aware it was connecting to itself. However this was a bug in earlier versions of the third party application which is now fixed, thus when mail delivery is attempted the following error is observed....

SYSERR(root): prevent config error: mail loops back to me (MX problem?)

I understand the concept behind this safety mechanism but it really is a pain when you have added appropriate configuration to route the messages appropriately based on the added custom header.

Note the third part app acts as a transparent proxy which is why it (correctly) thinks it is connecting back to itself.

Can this check anti mail loop check be disabled in any way ?

Best regards, Peter.

[Andrzej Adam Filip]

Add F=k flag to the relevant mailer to disable the check.
(Sendmail-8.7 and above)

e.g. to modify "relay" mailer in sendmail.mc use the following line:

MODIFY_MAILER_FLAGS(`RELAY', `+k')dnl

BTW The flag is used in submit.cf to disable such checks (see feature/msp.m4).

--
[Andrew] Andrzej A. Filip - https://www.linkedin.com/in/andfil