Enable Jumbo Frames Causes External Hostname Problem

As I said I have one system that doesn't work either and I now see what's special. I think it's because that's the one system I set to use jumbo frames along with my NAS. There was a second system of my kids that has jumbo frames enabled and I tried that one and sure enough it has the same problem. I have a switched network internally so the path from system to NAS is clear and 9k packets work. However my cisco e4200 router seems to not support jumbo frames at all. Pinging the internal and external IP with anything larger than a 1500 byte packet gets no response. I had erroneously thought the router's switch supported jumbo frames, but it doesn't and the way I have things switched fortunately means it mostly doesn't matter. But, for some reason if a PC which supports jumbos tries to talk to the NAS that supports jumbos through the router it doesn't work. This is pretty much what the OP is saying too I think. I do get the initial Auth challenge which means something is getting through, possibly the initial http hit is small enough, but then nothing. I'm wondering if we should expect this to work or if a networking guru would say of course that won't work. I work with a few guys who might know, I'll ask them when I get a chance.

steve