Hello there, I've recently connected a Cisco 871 router to a ISA 2004 server (site to site VPN). The connection details are listed in this Microsoft article:
http://technet.microsoft.com/en-us/libr ... 02442.aspx
The tunnel works, but it tends to disconnect once every week. Additionally we can't write backups to a server at the remote end (we only get a 1 kb file, the rest doesn't get transfered). The same goes for files that are sent by a scanner to the server.
A article detailed that mismatched MTU values might be the cause of this. I've adapted the ISA to negotiate the MTU (by setting the EnablePMTUDiscovery to 1), but this didn't solve the problem. A additional problem is that the tunnel won't form after a restart when IKE fragmentation is enabled.
Has anybody got any tips to solve these problems?