MTU breakage in f20

[Ed Greshko]

On 11/03/14 08:16, Wolfgang S. Rupprecht wrote:
> 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 at 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 at 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 at arbol ~]$ 

[egreshko at meimei ~]$ ip link show p128p1
2: p128p1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000

[egreshko at meimei ~]$ ping -s 1200 wifi   (my gw)
PING wifi.greshko.com (192.168.1.1) 1200(1228) bytes of data.
1208 bytes from wifi.greshko.com (192.168.1.1): icmp_seq=1 ttl=64 time=0.487 ms
1208 bytes from wifi.greshko.com (192.168.1.1): icmp_seq=2 ttl=64 time=0.501 ms


[egreshko at meimei ~]$ ping -s 7000 wifi
PING wifi.greshko.com (192.168.1.1) 7000(7028) bytes of data.
7008 bytes from wifi.greshko.com (192.168.1.1): icmp_seq=1 ttl=64 time=0.563 ms
7008 bytes from wifi.greshko.com (192.168.1.1): icmp_seq=2 ttl=64 time=0.511 ms

[egreshko at meimei ~]$ ping -s 500 wifi
PING wifi.greshko.com (192.168.1.1) 500(528) bytes of data.
508 bytes from wifi.greshko.com (192.168.1.1): icmp_seq=1 ttl=64 time=0.423 ms
508 bytes from wifi.greshko.com (192.168.1.1): icmp_seq=2 ttl=64 time=0.458 ms

So, no trouble here.  Fully updated F20 system.

-- 
If you can't laugh at yourself, others will gladly oblige.