Hello List,
My Setup: Baruwa puppet toaster (Web front end for Mailscanner with exim as MTA) on CentOS 5 passing mail to Exchange.
The Problem: external senders are getting a delay DSN on their end. Mail usually comes through to us though, but can take up to 24 hours!
What I've found so far: looks like exim is blocking the emails for certain senders. Log files from /var/log/exim/reject.log are littered with host lookup errors as such
(names & ip's changed to protect the innocent)
2013-02-17 08:25:49 H=(owa.mycustomer.com) [XXX.XXX.XXX.XXX] F=<them@???> temporarily rejected RCPT <me@???>: host lookup deferred for reverse lookup check
2013-02-17 08:26:50 H=(owa.mycustomer.com) [XXX.XXX.XXX.XXX] F=<them@???> temporarily rejected RCPT <me@???>: host lookup deferred for reverse lookup check
2013-02-17 08:27:51 H=(owa.mycustomer.com) [XXX.XXX.XXX.XXX] F=<them@???> temporarily rejected RCPT <me@???>: host lookup deferred for reverse lookup check
2013-02-17 08:28:52 H=(owa.mycustomer.com) [XXX.XXX.XXX.XXX] F=<them@???> temporarily rejected RCPT <me@???>: host lookup deferred for reverse lookup check
2013-02-17 08:29:53 H=(owa.mycustomer.com) [XXX.XXX.XXX.XXX] F=<them@???> temporarily rejected RCPT <me@???>: host lookup deferred for reverse lookup check
2013-02-17 08:30:54 H=(owa.mycustomer.com) [XXX.XXX.XXX.XXX] F=<them@???> temporarily rejected RCPT <me@???>: host lookup deferred for reverse lookup check
(Why every minute? even after the message is delivered?)
I've done a reverse dns lookup on the owa.mycustomer.com and found it exists.
I looked at the exim mailing lists for similar problems/resolutions and did find similar issues with the resolution being adding the ip to a whitelist. I added the whitelist to the /etc/exim/exim.config (
http://pastebin.com/xsSpNHNi) and the ip address to the file /etc/exim/skiprdns, however this has had no effect. Looking into it further, the error message is built into the source. Now I don't want to change the source, I just want to whitelist this ip to bypass the dns lookup. Any ideas on the root cause of this problem and it's solution?
Any help would be appreciated. Thank you!
Best Regards,
Mike Marcott
