I recall working on a customer host that I was ssh'd into. If I did an operation that displayed a bunch of text, the session would freeze up. It wouldn't freeze if I only did a bit of text at at time though. On a whim, I tried lowering the MTU, set it to something like 1000 and it worked without freezing on me. Was able to raise it to 1460 (I believe) and still work, but anything beyond that I would get the session lockups on more than a few sceens of data.
Later I researched it, and they were blocking all of ICMP which not only killed ping, but messed with mtu path discovery. Found some information about it on a Cloudflare blog: https://blog.cloudflare.com/path-mtu-discovery-in-practice
Later I researched it, and they were blocking all of ICMP which not only killed ping, but messed with mtu path discovery. Found some information about it on a Cloudflare blog: https://blog.cloudflare.com/path-mtu-discovery-in-practice