R61 NGX keeps dropping connections to other routers

[Paraic]

Hi,
Just installed the Trial version on a 3 interface (Internet, DMZ and Internal) SecurePlatform server. Behind the internal interface is a cisco 1721 with a WAN link to our hosting centre.
The routing works fine but after an hour or so FW-1 drops the connection and I have to re-connect. Routing is currently pointing to FW-1 for this WAN link which then routes to 1721.

When I connect directly to the 1721 bypassing FW-1 it works flawlessly.
Are there some timeouts on routing or something resetting on FW-1 that I'm not aware of?
Any setting I can check?
Any other ideas?

thnx
Paraic

[Sergej]

Check these:
1. Duplicated addresses (IP address conflicts)
2. Proxy ARP issues
3. Routing

P.S. Look for console output of Cisco router if there is some valuable messages.