Hi,

One of our clients uses a Cisco network and we have to connect to them using the Cisco VPN client. We can connect fine however our Draytek is blocking all traffic though (cant get anything though or from the other side over VPN)

Searching about this seems to be an issue with SPI but we cant disable it as theirs no options (and possibly not feasible) the crappy BeBox which up to now we were using in bridge mode doesn't have this issue but were now having to run two internal lans which is causing us a lot of grief and a support headache not to mention keeping us online with both ISPs involves lots of magic.

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Have you checked whether the cisco VPN network is on the same LAN IP subnet as the Draytek? If it is, that'd cause the problems that you're seeing.
Also, check whether the router's DoS defense (under firewall) is enabled, the UDP flood defense could cause that too.

Nope were on a 172. subnet with the vpn being on a 10.

Its purely the draytek. If I plug in the ADSL2+ Modem here and configure it for standard DHCP and Nat on 192.168.1.x everything works fine. Configure the draytek for the same range and put the ADSL2+ modem into bridge mode then everything works but.

At the moment were having to run the ADSL2 modem on a parallel subnet and dual home our machines with set static routes in windows just to get it working.