On Mon, 2007-10-29 at 14:00 +0000, Mark Rogers wrote:
Martijn Koster wrote:
If things are really how I thought I understood them to be then something about that article doesn't read right. You shouldn't have to set the MTU at both ends considering the other. You simply set the MTU at each end to something appropriate for the connection it has. Then the appropriate MTU for a given connection should be determined by Path MTU or worked around with allowable fragmentation. Setting all your interfaces to an MTU that low might work around an MTU mismatch somewhere simply because the figure is so low.
But by doing that you will increase the ratio of data to tcp overhead.
It could fix your ssh problem but I suspect it will have quite a negative effect on any local traffic on the same interface.
What should happen is that Path MTU should discover the lowest MTU in the route and operate to that. The way I understand it blocking ICMP at either end will break PMTU. Also some sites (and presumably some networks) are broken in that they don't cooperate with PMTU and don't allow fragmentation either which means that if you aren't set to the correct MTU you can't talk to them.
Also check the MTU setting on your Broadband router/interface 1458 is a figure that gets mentioned a lot but it is really dependant on the ISP and encapsulation type of your connection (AOL for example often requires 1400)