On Fri, 23 Jan 2015, Mikael Abrahamsson wrote:
Anyone know how I can check in OSX for what destinations it has received
PTB packets and what the PMTU it think it has for these destionations?
Found it:
$ netstat -f inet6 -narlW
Internet6:
Destination Gateway Flags
Refs Use Mtu Netif Expire
default fe80::9272:40ff:fe07:cc74%en0 UGc
14 0 1500 en0
...
$ netstat -f inet6 -narlW | grep -v 1500 | grep en0
2620:109:c007:102::5be1:f881 fe80::9272:40ff:fe07:cc74%en0 UGHWIi
2 237 1280 en0
2a00:1450:4005:801::1017 fe80::9272:40ff:fe07:cc74%en0 UGHWIi
1 454 1280 en0
2a00:1450:400f:804::2000 fe80::9272:40ff:fe07:cc74%en0 UGHWIi
2 73 1280 en0
2a00:1450:400f:804::200e fe80::9272:40ff:fe07:cc74%en0 UGHWIi
2 1476 1280 en0
2a00:1450:400f:805::2003 fe80::9272:40ff:fe07:cc74%en0 UGHWIi
1 20 1280 en0
2a00:1450:4010:c07::bd fe80::9272:40ff:fe07:cc74%en0 UGHWIi
1 820 1280 en0
So I guess the problem this time was some Google servers sending me
PTB=1280 and then Chrome not taking this into account when sending UDP
packets when using QUIC, resulting in fragmented IPv6 packets (which works
very badly in real life), and then not handling this situation by doing
fall-back to something else.
--
Mikael Abrahamsson email: [email protected]
