Tuesday, December 22, 2009

452 4.3.1 Insufficient system resources

A specific application we use for CRM was having issues with erratic email sending.
An issue was observed as an error in SMTP as “452 4.3.1 Insufficient system resources”
This error could be reproduced by hitting one of our Hub Transport Servers with any computer able to smtp to it
Based on smtp security hitting the other server giving the following (and correct error) proving the service was operating correctly but refusing me based on relay permissions
“421 4.3.2 Service not available, closing transmission channel”

We are running a dual Hub Transport Setup for HA (High Availability)

Error Message:

It looks like although both server are redundant smtp servers (Hub Transport Role);
*assumption* the specific server using them for SMTP sending has no redundancy set in its attempts at hitting an smtp server so although one was having issues it never fell over to the other, normal mail did fall over and thus why the issue only affected this specific app and not all mailflow.

The problem server had run below 1gb of disk space on the primary partition (C:) and Exchange 2007 SP1 has a setting that is called “Back Pressure” and if certain stats break rules since the queue is in a Jet Database now it will stop things to ease the pressure on resources (such as too much memory or too high an I/O level or in this case, too little disk space for the queue/logs). This explains why the issue was intermittent as the back pressure service kept turning itself on and off.

Sufficient data was moved from the C drive to the D drive,D Drive contained 40gb of disk space

This freed the initial space, to prevent this issue happening again i followed the Microsoft article on how to move the queue and logs


This moves both the queue database and the queue logs to prevent this issue from cropping up again, should the issue reoccur then the queue and logs are not to blame, this will assist in a process of elimination should the issue come up again.

As per the above linked Microsoft article, the following changes were made

C:\Program Files\Microsoft\Exchange Server\V14\Bin\EdgeTransport.exe.config
Was backed up as
C:\Program Files\Microsoft\Exchange Server\V14\Bin\EdgeTransport.exe.config.backupfile
And In:
C:\Program Files\Microsoft\Exchange Server\V14\Bin\EdgeTransport.exe.config


Changed to

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