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TCP handshake failing after inital SYN


I did a Wireshark capture recently and found a situation that I do not understand. Yellow is my server and blue is the server that I'm trying to contact. wireshark capture

I don't understand what happened in this situation, I have found multiple instances of this pattern. Would this cause any problems at the HTTP.

asked 15 Jan '16, 08:01

amir20001's gravatar image

accept rate: 0%

2 Answers:


This would cause, that the HTTPS or HTTP communication will not happen. Because the session won´t be established.

But a more detailed explanation is only possible with a trace and not with that kind of screenshot.

answered 15 Jan '16, 12:03

Christian_R's gravatar image

accept rate: 16%


If possible, you should provide the trace Christian suggests. Maybe anonymize it if you need to.

I would also ask whether you know the connectivity from your server to the server you're trying to contact? You should have gotten a synack response from that server. Instead, from your screenshot, you just got got an ack, which suggests to me that you there's some sort of proxy between your server and the other server.

answered 01 Feb '16, 12:55

jeantunis's gravatar image

accept rate: 0%