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Looping emails

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=3385
Printed Date: 30 November 2025 at 1:32am


Topic: Looping emails
Posted By: Guests
Subject: Looping emails
Date Posted: 06 April 2004 at 4:13pm
I have noticed that some emails that are rejected keep trying to get sent in every five minutes by the orginating server.  This is not true of all emails, but a significant number of servers will not stop trying to send in a message until it is accepted.  Can you alter whatever is sent back to the orginating server to tell it the message was accepted, even if I am going to tag it as spam and toss it in the quarantine.  Otherwise we are wasting a ton of space and bandwidth in getting hit with the same messages every five minutes.


Replies:
Posted By: Guests
Date Posted: 06 April 2004 at 10:35pm
I think if you send a message "accepted" back to the sending server you will also confirm that the destination is valid and you will end up getting even more spam due the address being verified as valid and accepting email. I would rather the server think the message was rejected and if it is a continual thing just blacklist the server.

Posted By: LogSat
Date Posted: 07 April 2004 at 1:30am

Doug,

What you're asking does violate the RFCs, since if an email is not delivered the remote server MUST be notified. However in our opinion the RFCs need to be updated, since they were written when spam did not exist...

In the latest builds of SpamFilter v2.0 we added a couple of options that should give you the functionality you request. Below is an excerpt of the new readme.html http://file:" CLASS="ASPForums" TITLE="WARNING: URL created by poster. - http://file:

The following custom parameters in the [server settings] section of the SpamFilter.ini file can be used to change default behaviors.

;Setting DoNotSendNDROnQuarantine to 1 will prevent generation of NDR when email are quarantined by causing SpamFilter *not* to send an error code when quarantining emails
DoNotSendNDROnQuarantine=0

That option is global to SpamFilter. All emails that are classified as spam will not generate NDRs. Some blacklists also allow you to add a :NULL suffix to them. This will cause only the emails that match that blacklist entry to be sent to NULL and will not generate NDR (they won't be quarantined either).

Hope this helps,

Roberto F.
LogSat Software

Posted By: keizersozay
Date Posted: 07 April 2004 at 11:10am
If the number of email servers hitting you like this isn't that big I would just create an access list on your router or firewall to block them from connecting to your SpamFilter server... that is of course as long as you don't need to communicate with them through email.

Posted By: Desperado
Date Posted: 10 April 2004 at 4:22am

WARNING:  This message serves no useful purpose what so ever!

The looping problem is a big issue and I have had the "Scrap the RFC's and start over" discussion at many different levels.  Lotus Notes is a real big killer.  Imagine this (I did not have to imagine it!) 2 LN users go on vacation at the same time and each one leaves an "out of office" flag.  The system Administrator is a Bozo and leaves all the bounce settings to the out of the box settings.  User one suddenly remembers that he forgot to send a drawing of 10Meg to user 2.  User 2's Max mailbox size is 6Meg so it get bounced.  Notes, by default, sends the entire message back.  User 1 is allowed 20Meg in his box but his administrator had set a 5Meg limit on inbound mail while allowing 20Meg outbound.  OK ... Do I need to go any further.  This happened on a Friday afternoon (not our server thank you) and the customers servers passed the messages back anf forth ALL weekend.  Both networks became bandwidth crippled and both servers creshed.

So ... use the no ndr setting where ever you can and the same for the null settings and the hell with RFC in this case.  You will still run into loop issues but not as many.  We use WebShield SMTP and it is designed to prevent looping but we still get into it sometimes.

Regards,

Dan S.


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