What I haven't found out is when the IP tunnels were introduced in the IOS= . It seems to be in IOS 11.2. So it is included in all recent versions, but the Cisco 2500's have limited flash and RAM capabilites. Therefore the recent IOS's cannot be used with older hardware. I suppose the IOS 11.2 should be sufficient for tunneling DECnet over IP. GRE 9.21s that was renamed 9.20.. I wanted to talk Chaosnet over IP and we wanted a generic way of doing foo-over-IP. But, before the GRE code worked Kirk broke Chaosnet, so there is no official release that does GRE and Chaosnet .._:) -P