I would like to get PP to set the DoNotFragment bit on each packet so I can increment the packet size and find out what router is limiting packets to 1472 bytes. I can use the MS ping 10.10.10.2 -f -l 1473 and see that "something" in the path is limiting the size, but I cannot tell which hop is the problem.

Hi.

It's not possible to manipulate the Do Not Fragment bit on outgoing PingPlotter packets, which means PingPlotter can't explicitly show that.

You could certainly use the Ping command along with the route discovered by PingPlotter to see where you start getting a return ping. This is a bit imperfect as some routers don't respond to ICMP echo requests explicitly targetted at them, but that happens rarely enough that I'd suspect using a combination approach would be pretty effective.

Sorry we don't have a better answer for you (and also sorry about the long response time - somehow this question slipped past the "new message posted" notifier).

- Pete

OK, thanks. I just tried what you said and it works just fine in this case. The offending router responded and I now know who to talk to.