A quick'n'dirty Path MTU discovery script in Python that automates repeated
calls to ping to perform binary search.
Sometimes the network is unusable without manually decreasing the MTU on the interface. This script should tell you what the appropriate value is.
$ ./pmtu example.com
750: 64.0 % packet loss
1125: 50.0 % packet loss
1312: 73.0 % packet loss
1406: 54.0 % packet loss
1453: * * *
1429: 50.0 % packet loss
1441: 44.0 % packet loss
1447: 0.0 % packet loss
1450: 61.0 % packet loss
1451: 54.0 % packet loss
1452: 37.0 % packet loss
>>> optimal MTU: 1452 + 28 = 1480
$ ip link set mtu 1480 dev wlan0
It's really quick'n'dirty, just about usable for my personal purposes.
BSD 3-clause.