Exchange 2003 SMTP service causing high latency
Posted on 2011-03-09
A client has an Exchange 2003 server. Usually, pings to the outside world reply in around 30ms but they now take anywhere between 300 - 800ms.
Stop the SMTP service on the server and latency returns to normal. Start it up again and after a few seconds the latency has crept back up agian.
I've enabled detailed logging on the SMTP connector and can see that there's a lot of SMTP activity. In particular, one user is mentioned a lot in reference to sending an email with a 15MB attachement to a yahoo address. I assume this is connected to my problem.
In the queue viewer I can see a couple of queues. One of the queues is for yahoo.com and is active. However, there are no messages in the queue when you open it up and click 'Find Now'.
Bandwidth on the broadband connection actually seems ok and largely unaffected by this. However, ping tests are bad.
My question seems to be this - If there's nothing in the queue, then why is the log file reporting so many communications with the yahoo server?
The 15MB attachment seems the likely culpret but I can't delete the message from the queue because I can't see it!