You need to raise your MTU above that on the other side and do a ping size sweep. Unlike at Layer-3 when you can use set a DF bit and get back an ICMP error, at Layer-2 when you exceed the far side's MTU, the packets are silently dropped.
Paul Vinciguerra CCIE# 10291 120 W Park Avenue, Suite 308 Long Beach, NY 11561 P: 516-977-2095 . F: 516-977-2482 . TF: 866-998-4624 vinciconsulting.com -----Original Message----- From: Tom Taylor [mailto:tom.taylor.s...@gmail.com] Sent: Friday, August 31, 2012 9:30 AM To: NANOG list Subject: MTU mismatch on one link Has anyone run into a situation where the MTU at one end of a link was configured differently from the MTU at the other end? How did you catch it? In general, do you see any need for a debugging tool to be standardized to find such mismatches? Tom Taylor
