>> A while back I was having networking issues. I eventually tried >> drastically lowering the MTU of all the systems onsite and the issues >> disappeared. I always thought the issue was due to the MTU on our >> modem/router. Today I read that AT&T DSL requires a 1492 MTU so I >> increased the MTU of our systems up to 1492 and haven't had any >> issues. Do certain ISPs require you to change the MTU of your entire >> network, or is this likely due to our AT&T modem/router itself? > > Are you using tunnels or a firewall that blocks related "icmp > fragmentation needed" packets?
I have this in shorewall/rules: ACCEPT all all icmp - - - 10/sec:20 Which I believe accepts all icmp packets but throttles them to 10/sec to avoid being flooded. Is that OK? > Please also try to find out if you're experiencing packet loss. If > fragmented packets cannot be reassembled due to some packets lost, you > will probably find connections freezing or going really slow. I will watch the output of ifconfig today to see if there are any RX or TX errors. - Grant
