On 01/04/2015 07:21 PM, David Collier-Brown wrote:
From a different rogers subnet, I get a default of 56, successes with 1500-byte pings to the router and to the outside world, but failures internally talking to rogers DNS servers
I assume you meant 576, not 56. Do you see an IPv6 link local address on that interface? It starts with fe80.
First, the dns server: $ cat /etc/resolv.conf # Generated by NetworkManager nameserver 64.71.255.204 nameserver 64.71.255.198
$ ping -s 1500 64.71.255.204 PING 64.71.255.204 (64.71.255.204) 1500(1528) bytes of data. ^C --- 64.71.255.204 ping statistics --- 19 packets transmitted, 0 received, 100% packet loss, time 17999ms
$ ping 64.71.255.204 PING 64.71.255.204 (64.71.255.204) 56(84) bytes of data. 64 bytes from 64.71.255.204: icmp_seq=1 ttl=58 time=7.63 ms 64 bytes from 64.71.255.204: icmp_seq=2 ttl=58 time=7.35 ms ^C --- 64.71.255.204 ping statistics --- 2 packets transmitted, 2 received, 0% packet loss, time 1002ms rtt min/avg/max/mdev = 7.350/7.492/7.635/0.166 ms
Second, ACM.org $ ping -s 1500 acm.org PING acm.org (64.238.147.76) 1500(1528) bytes of data. 1508 bytes from ACMWEB16.acm.org (64.238.147.76): icmp_seq=1 ttl=49 time=42.5 ms 1508 bytes from ACMWEB16.acm.org (64.238.147.76): icmp_seq=2 ttl=49 time=44.1 ms 1508 bytes from ACMWEB16.acm.org (64.238.147.76): icmp_seq=3 ttl=49 time=44.5 ms 1508 bytes from ACMWEB16.acm.org (64.238.147.76): icmp_seq=4 ttl=49 time=44.2 ms 1508 bytes from ACMWEB16.acm.org (64.238.147.76): icmp_seq=5 ttl=49 time=52.9 ms 1508 bytes from ACMWEB16.acm.org (64.238.147.76): icmp_seq=6 ttl=49 time=44.1 ms ^C --- acm.org ping statistics --- 6 packets transmitted, 6 received, 0% packet loss, time 5007ms rtt min/avg/max/mdev = 42.576/45.430/52.995/3.445 ms
This is similar to what I'm seeing. When I ping your DNS, I can do so with 1472, but not 1473 byte packets. I also see that 1472 limit from my notebook, but not my desktop, when going out to the Internet. I do not see it when pinging from my notebook to a computer on my local LAN. When pinging www.yahoo.com from my desktop system, I can ping with 1500 bytes. I'm not sure why 2 computers on my network get different results to Yahoo. Or where that 1472 limit is coming from.