Mail stopped flowing through Mail Gateway

[Ahochau]

Nothing changed in our configuration in the last 2 years. Suddenly has begun rejecting mail from external senders. Here is the error we are getting:

[<My Pubic IP>]
Remote Server returned '554 5.0.0 <[My Pubic IP>] #5.0.0 smtp; 5.1.0 - Unknown address error 554-'5.7.1 <user@mydomain.com>: Recipient address rejected: Rejected by SPF: <My Pubic IP> is not a designated mailserver for sender%40remotedomain.com (context mfrom, on <smtp.mydomain.com>)' (delivery attempts: 0)>'

So it appears the message is coming in from the internet, and then being routed to my public MX record back into the mail gateway which is causing the messages to be rejected. My mail gateway sits in a DMZ and uses internal DNS servers for resolution. All DNS checks result in the proper IP being resolved.

 

[Stoiko Ivanov]

* on a hunch - I guess that something changed in your network (could also be an upgrade to a router provided by your ISP - i.e. nothing which you actively changed ) ?

the could you please share the logs as they are on the PMG (if possible take them from the tracking center of from /var/log/mail.log) - I currently can't seem to get the complete picture - but :

#5.0.0 smtp; 5.1.0 - Unknown address error

might indicate that the server rejecting the message is an Exchange? (PMG does AFAICT not use this error - message)

I hope this helps!

 

[Ahochau]

Exchange servers on the inside, Office365 on the outside where I am able to receive the error message. Sending from gmail and live the mail just never arrives. Customers have said they are getting strange bounces. I disabled using the mx on the mail proxy and send inbound directly to the internal servers, but it still appears to be relaying back out to itself.

 

[hata_ph]

Check your SPF settings.