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Issue on 4.5.0.28 against Qmail-LDAP

Printed From: LogSat Software
Category: Spam Filter ISP
Forum Name: Spam Filter ISP Support
Forum Description: General support for Spam Filter ISP
URL: https://www.logsat.com/spamfilter/forums/forum_posts.asp?TID=7020
Printed Date: 27 December 2024 at 8:37am


Topic: Issue on 4.5.0.28 against Qmail-LDAP
Posted By: roaridse
Subject: Issue on 4.5.0.28 against Qmail-LDAP
Date Posted: 25 May 2012 at 7:27am
Hi,

I have a lot of these error messages in my spamfilter-log - as far as I know we have never got a complaint of missing mails due to this errormessage - maybe because the mails are spam. 

05.25.12 13:18:51:722 -- (21851760) server error - lysefjorden.hesbynett.no:25 said: See http://pobox.com/~djb/docs/smtplf.html. --  - message queued - valriemuirenny@my.name-services.com

Is this something Spamfilter should be blocking as well?



Regards
Roar


Replies:
Posted By: LogSat
Date Posted: 25 May 2012 at 7:45am
Hi Roar,

From this message it seems that the SMTP server where you're forwarding the email to is performing SPF checks for spam. Please note that this should not be done, as those checks will likely always fail. SPF is used by the sender's domain to specify which IP addresses are allowed to send emails on their behalf. When SpamFilter forwards an email to your destination SMTP server, your destination SMTP server sees SpamFilter's IP address as the sender of the email, not the original IP that originally delivered the email to SpamFilter. If the email is valid, then the SPF check performed by SpamFilter will validate the sender's IP and pass on the email to your destination SMTP server. However if your destination SMTP server performs another SPF check, it will see SpamFilter's IP address as the sender and will reject the email, since SpamFilter's IP will unlikely be in the SPF record for the sender to authorize it to send emails.

This said, if the email was spam, and the SPF record for the sender was configured properly, SpamFilter should have rejected the email if you had the SPF filter enabled and the email was not whitelisted for some reason. If you can zip and email us SpamFilter's activity logfile (possibly trimmed to the 10 minutes before and after 05.25.12 13:18:51:722 at which the email was received) we can go thru it to see what happened.


-------------
Roberto Franceschetti

http://www.logsat.com" rel="nofollow - LogSat Software

http://www.logsat.com/sfi-spam-filter.asp" rel="nofollow - Spam Filter ISP

Posted By: roaridse
Date Posted: 25 May 2012 at 8:29am
Hi,

It is not doing SPF checks, but it complains for missing CRLF linechanges, the mails arrives with only LF. 

I know that the receiving mailservers should not use SPF-checks. 

When speaking about SPF, you reminded me on another case I have noticed lately:

05.25.12 14:24:00:037 -- (21855600) - SPF DNS error: - Invalid Packet Size 3
05.25.12 14:24:02:725 -- (107680496) - SPF DNS error: - Invalid Packet Size 3
05.25.12 14:24:19:085 -- (116418688) - SPF DNS error: - Invalid Packet Size 3
05.25.12 14:24:50:241 -- (107609456) - SPF DNS error: - Invalid Packet Size 3
05.25.12 14:24:54:819 -- (107684208) - SPF DNS error: - Invalid Packet Size 3
05.25.12 14:25:04:194 -- (116417152) - SPF DNS error: - Invalid Packet Size 3

Any ideas what this is? 

The DNS-servers used by Spamfilter is 81.29.32.130 and 81.29.32.135, where the first is running PowerDNS recursor, and the other is running BIND. 


Roar


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