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TCP Session Timeout Ignores Activity

In troubleshooting an Outlook/Exchange server dropped connection issue, we were able to isolate the issue to the RV180W (current firmware) TCP Session Timeout setting.  The connection used is RPC over HTTPS and the Exchange Client Access Servers are set to send a keep-alive every 2 minutes.  We also set the local devices to send a TCP keep-alive every 10 minutes.  The RV180W was set to timeout after 30 minutes of idle time (according to the Help description).  Outlook would recognize its connections were severed if there was no email activity for over 30 minutes.  Replacing the router with another brand running DD-WRT exhibited no issues.  Setting the RV180W timeout to 10 hours removed the issue for during the work day (most workstations are on for less than 10 hours each day).

From reviewing some notes on other router models, this appears to be an issue with Cisco firmware across the small business routers in one form or another.  I fully expected that a 10 minute TCP keep-alive would have prevented the router from severing (there is no FIN, SYN, etc. sequence that I can determine) the connections but it did not.  It appears that small packets are either ignored or the firmware is losing track of activity on open TCP connections.

This is a standard NAT configuration with no special configuration settings for Outlook/Exchange.  The "10 hour session timeout fix" will remain in place until Cisco confirms resolving this issue in a future firmware release.

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