Sonicwall resetting connections (For no apparent reason)

We have a Sonicwall Pro 3060 that is transparently bridging traffic to the Internet and a VPN to another site. We are having connections being reset for no apparent reason. For instance, connecting Outlook to our Exchange server at the other site. Once every 2-3 minhutes on average, the connection is being reset, and Outlook looses connectivity. Through packet captures, I have confirmed that the Sonicwall is generating a reset packet, and sending it to the client, as if coming from the exchange server.

We have gone through everything we can think of, and have so far come up with nothing.

Any thoughts on why the sonicwall would be doing this?

Josh

From serverfault Josh Brower

• Apparently SonicOS can embed "reason codes" into TCP RST packets. You might look at this doc and compare it to what you're seeing in your packet captures.

  Josh Brower : Unfortuantly, I dont see any "reason codes" embedded in any of the rst packets.
  From Evan Anderson

• If you read the document that Evan referenced in his post you'll see that one of the components that will issue a reset is in fact, a Cache Cleanup function related to expired connection timers. This is the "idle session" clean up that I'm referring to. That's my bet as to the cause of the problem.

  Josh Brower : This would also be my best guess, but we could never figure it out; so we moved the VPN up to the router, and it fixed it.
  From joeqwerty