MTU problems that look like random hangs

Back to list2026-08-21
You

Large responses hang while small ones work.

ChatGPT

Classic MTU or path MTU discovery failure, usually with a tunnel in the path. Test by lowering the MTU on one side and retrying; if it fixes it, the real problem is ICMP being blocked somewhere, which is what breaks discovery.

You

Any downside worth knowing before I commit?

ChatGPT

It commits you to a format that is tedious to migrate away from later. The first weeks also look worse than doing nothing, which is when most people abandon it.