It looks like something broke recently that severely limits the MTU in
Fedora 20 when running under NM. Are other people seeing this too?
Here I'm pinging my upstream lan-to-wan gateway. A 1200 byte ping fails
while a 500 byte one succeeds. I see the same thing when pinging
between two identical, fully up-to-date f20 systems.
wolfgang@arbol ~]$ ping -s 1200 gw
PING
gw.wsrcc.com (192.168.35.1) 1200(1228) bytes of data.
^C
---
gw.wsrcc.com ping statistics ---
3 packets transmitted, 0 received, 100% packet loss, time 2000ms
[wolfgang@arbol ~]$ ping -s 500 gw
PING
gw.wsrcc.com (192.168.35.1) 500(528) bytes of data.
508 bytes from
gw.wsrcc.com (192.168.35.1): icmp_seq=1 ttl=64 time=0.503 ms
508 bytes from
gw.wsrcc.com (192.168.35.1): icmp_seq=2 ttl=64 time=0.460 ms
508 bytes from
gw.wsrcc.com (192.168.35.1): icmp_seq=3 ttl=64 time=0.456 ms
508 bytes from
gw.wsrcc.com (192.168.35.1): icmp_seq=4 ttl=64 time=0.454 ms
^C
---
gw.wsrcc.com ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3001ms
rtt min/avg/max/mdev = 0.454/0.468/0.503/0.025 ms
[wolfgang@arbol ~]$
-wolfgang