>> Rather than guess and take random values read on the net - measure it. >> >> Google calculate mtu - netgear and others show ways to test upstream to >> get the ideal size using ping >> >> You are looking for the largest MTU value before fragmentation starts to >> occur. > > See https://www.dslreports.com/faq/695 for detailed instructions on > getting the maximum MTU for your setup.
I followed the instructions and got this at first: # ping -s 1472 www.dslreports.com PING www.dslreports.com (64.91.255.98) 1472(1500) bytes of data. >From dsldevice (192.168.1.254) icmp_seq=1 Frag needed and DF set (mtu = 1492) 1480 bytes from www.dslreports.com (64.91.255.98): icmp_seq=2 ttl=54 time=93.9 ms After that it wouldn't tell me "Frag needed" no matter how high I set the MTU for the ping command, but maybe the above indicates that my max MTU is 1492? - Grant
