Please accept my apology if this isn't the appropriate place to post. If it isn't, a suggestion as to the correct group would be appreciated.
I have a client who has 3 locations. At the main location is a DLink DFL200 that has been working great for years. Each of the remote locations have a DLink DFL300 as the gateway router on a static IP internet connection. Both DFL300s have the same firmware level, and all of the VPN settings are identical, except for the inside IP block (one is 192.168.4.0/24, the other is 192.168.2.0/24), and the PSK.
The DFL300 at the 192.168.2.0/24 end works flawlessly. The one at the192.168.4.0/24 experiences a two minute drop of the VPN tunnel every 50 minutes.
There is very little traffic on either tunnel -- they are used to provide telnet sessions, remote lpr printing, etc., to/from an ancient SCO Unix system at the main location.
I've searched Google, forums, Broadband reports, etc., exhaustively for a solution to this problem. The only common thread I've seen has to do with changing the MTU setting. We tried setting the problem DLink's MTU to 1400 and 1300, but still get the same results (2 minute dropout every 50 minutes).
Any suggestions would be greatly appreciated.