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Comunication over VPN (2 Servers)


Hey guys,

I have a little problem and only wanted to know if I'm right.

MachineA: -

Sorry for Checksum Offload here!

MachineB: -

There's only the one stream in my trace file. What's going on there?

Regards Leo

asked 11 Jan '13, 08:06

DasLeo's gravatar image

accept rate: 0%

What exactly is the question ?

It looks like the captures are of a connection between the two machines as seen at each machine.

(11 Jan '13, 08:26) Bill Meier ♦♦

One Answer:


There's only the one stream in my trace file. What's going on there?

Well, there are some differences. Some minor, some major.

Minor: Some frames with the same IP ID are different in length: #3,#5,#8. However, that's not a problem, as the difference is due to removed padding bytes in the ethernet frame.

Major: Frame #18 (MachineA) was not transmitted over the VPN tunnel, as the size was too large (4192 bytes) and the don't fragment flag was set in that segment.

If your question is: How to fix the 'major' problem?

My answer would be: Check the MTU size of the involved systems and adjust it to the requirements of your VPN, or allow IP fragmentation.


answered 11 Jan '13, 12:05

Kurt%20Knochner's gravatar image

Kurt Knochner ♦
accept rate: 15%

Thx Kurt, that's what I needed to know!

(14 Jan '13, 23:18) DasLeo


HINT: If a supplied answer resolves your question can you please "accept" it by clicking the checkmark icon next to it. This highlights good answers for the benefit of subsequent users with the same or similar questions.

(15 Jan '13, 05:17) Kurt Knochner ♦