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Perminent or temporary?

Printed From: LogSat Software
Category: Spam Filter ISP
Forum Name: Spam Filter ISP Support
Forum Description: General support for Spam Filter ISP
Printed Date: 23 October 2017 at 4:51pm

Topic: Perminent or temporary?
Posted By: yapadu
Subject: Perminent or temporary?
Date Posted: 18 December 2010 at 9:58am
I have spamfilter to retry when it receives a 4xx error code from a remote server and bounce if it gets a 5xx error code.

Someone reported an issue where there server was not working right for a couple of days, but there were no messages in the queue.

A check of the logs shows this:

12/18/10 05:04:29:218 -- (3196) EMail from to --  was forwarded to
12/18/10 05:04:29:218 -- (3196) Some recipients do not exist, sending 550 to sender SMTP server. The destination SMTP server 451 Temporary local problem - please try later -- 

So what does this mean?  The remote server returned an error 451 (temporary problem, so we should queue) and then bounced the message to the sender with a 550 error?

I am a user of SF, not an employee. Use any advice offered at your own risk.

Posted By: LogSat
Date Posted: 18 December 2010 at 4:48pm

This case is a bit peculiar, as SpamFilter encountered a "user not found" when forwarding the email to the destination SMTP server. This initial forwarding is the one where SpamFilter behaves differently depending on the 4xx or 4xx errors. However SpamFilter received a "user not found" message, in which case SpamFilter needs to send an NDR (non-deliverable receipt) back to the sender. This NDR is forwarded to the destination SMTP server for delivery, but it is at this point that the " 451 Temporary local problem - please try later" is encountered. Errors received during NDRs are handles "less gracefully" by SpamFilter as continuing re-sending them could potentially cause email loops, so after one try they are usually dropped.

Please note that I may be mis-reading the log entry above, and would need to see the complete transaction (along with the log entries relative to the original email) to be more certain.

Roberto Franceschetti" rel="nofollow - LogSat Software" rel="nofollow - Spam Filter ISP

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