I'm going to throw this one out there, because it's causing me to bang my head against my desk very hard.
I've found a number of issues on a network I inherited, and I just need to clear my head with something.
If I ping an internal device from another internal device (i.e. a server from my PC), should i be able to ping with an MTU higher than 502?
Unable to ping anything internal / external with an MTU over 502, 510 = Request Timed Out