Hi Experts
I encountered an TCP handshake issue. Client initiated SYN(No.1 & 2) to server, however server responded an ACK(No.3) not SYN/ACK, but after that the server send a SYN/ACK(No.6) back to client.
According to pcap, it seems client retransmission the SYN till it RST this handshake. But somehow, the client try to re-establish the connection, and it worked normal as SYN , SYN/ACK , ACK.
My question is,
- What kind of situation will cause this issue happen?
- During handshake phase, what will client do if he received 2 ACKs ?
More Info:
- The dump is captured at server side interface.
- pcap file : https://dsc.cloud/CloudBucket/handshake.pcap
- Image : https://dsc.cloud/CloudBucket/Screen-Shot-2018-09-21-at-11.44.40-AM.png
Sorry for that I don't have point to upload here
Thank you,
Tom
