https://issues.apache.org/SpamAssassin/show_bug.cgi?id=6462
--- Comment #7 from Kevin A. McGrail <[email protected]> 2011-12-15 23:25:58 UTC --- Not sure if this is the original poster's issue but it's definitely an interesting bug and it's the reason for my issue. I'm going to post on the opendkim users list as well to see if anyone can give guidance. I've been working with AXB and others for a few weeks on a DKIM issue. Now, for my particular install, I know I have some DKIM failures because I purposefully modify the email body. But I've also been testing in a pure sendmail installation. The bug is a modified To: Header but I'm unsure why/what is changing the To: Header. The first emails are being tested with spamassassin called from procmail after using MD is called. I found that if AXB uses the Gmail web interface, all is good. However, he normally uses Thunderbird. I think that's a red-herring or just part of the problem though so keep reading. Now I have a trapped version of the email pre delivery / going through mimedefang, virus scanners, etc. etc. Testing it with opendkim on the command line shows the pre works and the post sendmail/md/procmail fails: [root@devel tmp]# opendkim -t - < gmailviatbird-predelivery.txt opendkim: (stdin): verification (s=gamma, d=gmail.com, 1024-bit key) succeeded [root@devel tmp]# opendkim -t - < gmailviatbird-postdelivery.txt opendkim: (stdin): verification (s=gamma d=gmail.com, 1024-bit key) failed: signature verification failed A diff and lots of trial and error testing showed that the failure was because of this: -To: "Kevin A. McGrail" <[email protected]> +To: "Kevin A. McGrail" <[email protected]> Specifically, the case change on the To: header. So what rewrote the To: header and why? The one thing I've been able to pin down is that if I use the gmail web-based interface and play around with case, the for part of the received header has the correct case and my DKIM tests work fine. However, when AXB uses thunderbird to send via gmail, the case sensitivity between the for in the received and the To header appears different. Now on a pure sendmail environment on a stock CentOS Installation, attached is an email AXB wrote via Thunderbird sent via gmail. Note that it will fail opendkim UNLESS you modify the to header to the correct email address he used to [email protected]. Somewhere along the way the To: header gets rewritten to all lower case. However, I couldn't reproduce this scenario with all my tests but I don't use anything but Gmail's web interface. So my conclusion is that Thunderbird or Gmail are somehow ending up with one case version of the to address as the for in the received header and a different case version in the to header. Then during delivery, either procmail or sendmail are "fixing" the To: header which is breaking DKIM. Anyone have any recommendations? Is this known behavior in sendmail or procmail? Something specific to Gmail and using an external client? Specific to Thunderbird? Regards, KAM -- Configure bugmail: https://issues.apache.org/SpamAssassin/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug.
