On 3/18/2010 1:43 PM, Kay wrote:
Hi guys,
I often see mail being rejected by recipient servers because an IP in a
Received From header is blacklisted somewhere.
This strikes me as a rather bad practise, since it undermines the whole
idea of SMTP authentication.
Here's an example reject:
550 5.7.1 This system has been configured to reject your mail. An IP
address (xx.xx.xx.xx) found in the message's 'Received:' headers is
listed by the lookup site 'sbl-xbl.spamhaus.org.'.
xx.xx.xx.xx is the client's IP, a regular dynamic IP on a broadband
connection. Which shouldn't have any relevance.
To make matters worse, the offending recipient site does not accept mail
for abuse/postmaster or any of the usual aliases.
How do you engage hosts like these to resolve such issues?
Thanks
K
Yes, this is very annoying. I communicate with a couple
misguided souls with similar rules. I imagine they all use
the same filtering software and just click some box without
understanding what it does.
Anyway, I use the following smtp_header_checks rule which
seems to fix the problem. I use smtp_header_checks so that
the mangling only happens on external delivery.
http://www.postfix.org/postconf.5.html#smtp_header_checks
/^Received: (.*by host\.example\.com \(Postfix\) with ESMTPS?A
id.*)$/ REPLACE X-Submission: $1
Of course, replace host\.example\.com with your own host name.
It's possible that some hosts will still choke on this, in
which case you will need to use IGNORE to remove the offending
header instead of just rewriting it, but I don't suggest
removing headers without good reason.
Of course it's a good idea to contact the other postmaster and
try to convince them of their error, but I haven't had much
luck with that... Part of the problem is no one there seems
to know what a "postmaster" is. Maybe you'll fair better.
-- Noel Jones
