Wireshark-users: [Wireshark-users] TCP Delta question

From: Tom Simpson <tosimpson@xxxxxxxxxxxxxxx>
Date: Thu, 21 Aug 2014 14:55:40 +0000
I am looking at a trace file  from a server and have a question.

I am seeing a large TCP Delta in some of the packets and the source server is the machine I have Wireshark installed on. 


Here is one of the packets that shows the large Delta.  I took a trace from the server on the other end and it shows a very small, what I expected it to be, Delta Time. Does this mean the server I am capturing on is possibly having an application issue of some sort? This was taken during a file transfer between the two; I copied Acrobat Reader from the fileserver to the terminal server. The transfer took a normal amount of time, so I am thinking this is some housekeeping process for M$AD. 



No.     Time                       TCP Delta  Source                Destination           Protocol Length Win Size   Calc'd Win Size 
41983 1408627378.013279          119.951789000 fileserver.mydomain.local terminalserver.mydomain.local TCP       55     64629      64629       [TCP Keep-Alive] microsoft-ds > 63239 [ACK] Seq=385 Ack=321 Win=64629 Len=1


This was a 1 byte keep alive which is what has me puzzled. I do see these same Delta times with similar traffic on some of our other servers on the network.  Does this mean there is an issue in AD, or is this just one more reason to use a TAP for a packet capture instead of installing wireshark locally on the server?





-- 
Thanks,

Tom Simpson
LAN/WAN Engineer
Forcht Group of Kentucky
859.259.9700 x538

"We all knew there was just one way to improve our odds for survival:
train, train, train. Sometimes, if your training is properly intense it
will kill you. More often -- much, much more often -- it will save your
life."  - Richard Marcinko, former US Navy SEAL Team Commander



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