How To Read Exim Logs for Forwarders

So a couple of months ago I was doing some tickets and I ran across a ticket with a sticky note from a tech. Here’s what was in the note (I’ve edited the addresses and names for privacy purposes):

Date: Thu, 01 Dec 2011 12:24:27 -0700


email is not forwarding. I’ve checked the dig on both domains and they look good. I’ve sent some test emails and they are not forwarding.

2011-12-01 12:16:51 1RWC7m-00032x-TQ 2011-12-01 12:16:51 1RWC7m-00032x-TQ => "customer" R=virtual_user T=virtual_userdelivery
2011-12-01 12:16:51 1RWC7m-00032x-TQ Completed

2011-12-01 12:23:23 1RWCE7-0007hM-RS 2011-12-01 12:23:24 1RWCE7-0007hM-RS => customer R=virtual_user T=virtual_userdelivery
2011-12-01 12:23:24 1RWCE7-0007hM-RS Completed

So I resolved the ticket and sent an email to the tech explaining what the exim logs actually mean. I’ll post my whole response, edited of course, below.

So you’re sending from to You see on the receiving line customer. The customer here is referencing the address it is being forwarded to. Here’s an example from my account:

2011-12-03 21:09:06 1RX3Ny-0002LQ-0G DKIM: s=gamma c=relaxed/relaxed a=rsa-sha256 [verification succeeded]
2011-12-03 21:09:06 1RX3Ny-0002LQ-0G R=alt_forwardproxy T=dk_remote_smtp_with_return_path H= [] C="250 ok 1322971746 qp 13362"
2011-12-03 21:09:06 1RX3Ny-0002LQ-0G Completed

You’ll notice where it has the address I forwarded to before the address I forwarded. There’s no @domain on “customer” because it is on the same host as the address it’s forwarding from. The guy’s most likely issue is what he’s checking the mail with. but the forwarders are working properly. let me know if you have more questions. Stay awesome.

Exim is clearly one of the more difficult things for people (including techs) to understand. I hope this post can help other to understand a little bit more.