Jim McIver wrote:

Here's a snippet from maillog, but not sure if it's what your looking for:

Thanks, this is very helpful.

Mar 4 15:10:13 mail postfix/smtpd[56190]: warning: Illegal address syntax from unknown[113.9.198.198] in MAIL co
mmand: bikedev...@yahoo.co.jp

The above client is listed in multiple RBLs, including zen.spamhaus.org, bl.spamcop.net, cbl.abuseat.org, b.barracudacentral.org, and dnsbl.sorbs.net.

Mar 4 15:10:15 mail postfix/smtpd[56172]: warning: 81.25.227.150: address not listed for hostname mail.medterm.o
d.ua
Mar 4 15:10:15 mail postfix/smtpd[56172]: connect from unknown[81.25.227.150]

This client is also listed in multiple RBLs.

Mar 4 15:10:15 mail postfix/smtpd[56190]: NOQUEUE: reject_warning: RCPT from unknown[113.9.198.198]: 450 Client host rejected: cannot find your hostname, [113.9.198.198]; from=<bikedev...@yahoo.co.jp> to=<odrawh...@dnews.com>
proto=SMTP helo=<yahoo.co.jp>

Clearly a forged HELO name. Grounds for rejecting any mail from this client.

Mar 4 15:10:15 mail postfix/smtpd[56190]: E35C331: client=unknown[113.9.198.198]

Mar 4 15:10:18 mail postfix/cleanup[56217]: E35C331: message-id=<20090304231015.e35c...@mail.lmtribune.com> Mar 4 15:10:18 mail postfix/qmgr[56169]: E35C331: from=<bikedev...@yahoo.co.jp>, size=966, nrcpt=1 (queue active
)
Mar 4 15:10:18 mail postfix/smtp[56178]: E35C331: to=<odrawh...@dnews.com>, relay=127.0.0.1[127.0.0.1], delay=3, status=bounced (host 127.0.0.1[127.0.0.1] said: 557 Invalid routing request - domain in BLACK LIST. (in reply to
MAIL FROM command))

What?? Some idiot content_filter at 127.0.0.1 is rejecting the mail after you've already accepted it.

Don't do that. Reject mail when first comes from the internet. Once mail has been accepted, a content filter must not reject the message.


Mar 4 15:10:18 mail postfix/cleanup[56175]: 5ABF260: message-id=<20090304231018.5abf...@mail.lmtribune.com> Mar 4 15:10:18 mail postfix/qmgr[56169]: 5ABF260: from=<>, size=2926, nrcpt=1 (queue active)
Mar  4 15:10:18 mail postfix/qmgr[56169]: E35C331: removed
Mar 4 15:10:19 mail postfix/smtpd[56190]: disconnect from unknown[113.9.198.198] Mar 4 15:10:20 mail postfix/smtp[56178]: 5ABF260: to=<bikedev...@yahoo.co.jp>, relay=mx1.mail.yahoo.co.jp[124.83 .171.181], delay=2, status=bounced (host mx1.mail.yahoo.co.jp[124.83.171.181] said: 553 VS10-RT Possible forgery or deactivated due to abuse (#5.1.1) bikedev...@yahoo.co.jp (in reply to RCPT TO command))

Yahoo didn't send this mail, and they don't want your backscatter bounce.

Eventually they (and others) will blacklist you for backscatter - ie. returning mail they never sent.

You must fix your content_filter to not reject mail. Choices may include tag+deliver, quarantine, or discard, depending on what your software supports. It may offer the choice of reject or bounce, don't do that.

You can also greatly reduce the load on the content filter by using one or two good RBLs to reject mail before it ever gets to the content_filter. zen.spamhaus.org is safe and very effective.


  -- Noel Jones

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