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question about headers

Posted: Sat Mar 31, 2007 3:31 pm
by audrey
Not Swift-related, precisely, but hopefully someone here can clue me in. I'm struggling with "the Hotmail problem" (they silently black hole my newsletter all of a sudden). I've implemented (correctly, i hope) SPF, and am checking a few other things to ensure that the email looks legit. Looking at the headers, i noticed something a bit odd. The server i'm using has a hostname domain1.org, but the mail is coming from another domain, domain2.org. So, first, i passed domain2.org to the constructor, so that the EHLO will use that one. So far, so good.

But one of the headers is:

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Received: from domain2.org (domain1.org [127.0.0.1]) ...
I thought that the 127.0.0.1 might be seen as a red flag (is it?) so i changed the the connection from 'localhost' to the IP of the sever. Testing this, i now see:

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Received: from domain1.org (unknown [M.Y.I.P]) by domain2.org ...
Does anyone know what the "unknown" is in reference to? And is it a bad idea to do this? I'm not too sure about the intricacies of fsockopen().

Posted: Sat Mar 31, 2007 9:51 pm
by Chris Corbyn
Many SMTP servers do a reverse name lookup based on your IP. So if you sent from <my ip> and your host doesn't provide rDNS for that domain then you'll see "unknown". Many SMTP servers actually require rDNS to proces the request. I'd stick with your first option; the 127.0.0.1 shouldn't be a red flag. Reverse DNS can return anything it wants, so even though 1.2.3.4 is test.tld, the rDNS may argue that it's test2.tld. This is pretty normal.

Have you checked your IP in: http://www.robtex.com/rbls.html ?

Also, is this *just* hotmail?