> From: Karl-Heinz Wild > i've a problem with dkim and yahoo. > > the log shows me something, it seems very special > ----------------------------------------------------------------- > 2014-09-23 12:00:06 1XWMtC-000Dzw-0C DKIM: d=yahoo.com s=s2048 > c=relaxed/relaxed a=rsa-sha256 t=1411466404 [verification failed - signature > did not verify (headers probably modified in transit)] > 2014-09-23 12:00:06 1XWMtC-000Dzw-0C DKIM: d=yahoo.com s=s1024 > c=relaxed/relaxed a=rsa-sha256 t=1411466404 [verification succeeded] > 2014-09-23 12:00:06 1XWMtC-000Dzw-0C DKIM TEST: domain=yahoo.com > possible_signer=yahoo.com status=fail reason=signature_incorrect > ----------------------------------------------------------------- > > as you can see there are two lines. one succeeded and the first fails. > the difference seems to be the s=1024 vs s=2048.
I just sent a few test messages via yahooMail ( @ yahoo.com ). Messages sent from a MUA (Opera Mail, like Thunderbird) in Eastern Europe via SMTP through smtp.mail.yahoo.com (with authentication) came from yahoo's datacenter in Ireland (nm14-vm7.bullet.mail.ir2.yahoo.com), each message has two DKIM-signatures: top one s=s2048 verification failed and bottom one s=s1024 verification succeeded. Messages sent from yahooMail's web-interfaces (Basic and FullyFeatured) came from yahoo's datacenter in Buffalo,NY (nm5-vm0.bullet.mail.bf1.yahoo.com), have only one DKIM-signature with s=s1024. Verification done by my Exim 4.83. I found an older message (05 Jul 2014) submitted from Thunderbird in Argentina via SMTP through smtp.mail.yahoo.com, it has two DKIM-signatures and came from yahoo's datacenter in Nebraska (nm10-vm4.bullet.mail.ne1.yahoo.com), so perhaps submitter's geolocation is irrelevant. I suspect that yahoos broke something when they did another stupid thing: mow messages submitted via SMTP don't show submitter's IP-address anywhere in the header (though messages submitted via web-interfaces do show submitter's IP-address in the bottom Received). -- ## List details at https://lists.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://wiki.exim.org/
