Wireshark-users: [Wireshark-users] Calculating PMTUD

From: <natrbrazell@xxxxxxx>
Date: Tue, 7 Oct 2008 13:18:12 -0400

When trying to ascertain the effect of devices inline on a network such as a cryptographic device, is it best to use 1514 (Total size seen in Wireshark) as the MTU at the host or 1500?  For instance if my PC's at either end of a connection  has MTU of 1500 and using a tool such as Iperf I discover that my MTU and MSS values are 1412 and 1372 for MSS, do I assume that the size is 1500 - 1412 or 1514 - 1412?

Thanks,
Nate