I've recently purchased a Cisco RVS4000 router. One feature of the router which appeals to me is the jumbo frame support. In anticipation for getting jumbo frames set I began doing some testing of the router and found some curious results.
With everything set at defalts (not attempting jumbo frame) I'll ping 192.168.1.1 -f -l 1473 from a windows xp workstation and I'll get "Packet needs fragmentation but DF set". This is what I would expect. However, when I ping 192.168.1.1 -f -l 1472 I get a request timed out message, which is not what I would expect. I get request timed out messages all the way down to 1,000 something at which point the packets go through fine. I get the same behavior pinging from different computers and/or different cables. When I plug in my old router and ping 192.168.1.1 -f -l 1472 the packet goes through just fine. Again with the old router, 192.168.1.1 -f -l 1473 produces a fragmentation message.
So is the RVS4000 blocking the pings as some sort of security feature or is there something wrong with the router?
Thanks for your help.