Wireshark · Wireshark-users: [Wireshark-users] Same SEQ number but different ACKs

["Sheahan, John" <John.Sheahan@xxxxxxxxxxxxx>]

I'm troubleshooting a problem with a 443 connection through a Squid proxy server.

The communication actually goes through but we are seeing RSTs at the end of every conversation after the FIN coming from the proxy server.

After looking at the packets, in the middle of the conversation, I am seeing the client send two packets with the same SEQ number with two different ACK values, at that point, I get a FIN for the duplicate SEQ number yet my client continues to send several more packets with the same SEQ (same as before the FIN) with different ACK values.

It is at that point that the proxy server sends a RST but the ACK value is way too high to match any of the previous SEQ numbers sent by my client.

 

I can understand a retransmission but am I correct in my thinking that I should never have a duplicate SEQ number with a different ACK value?

 

thanks

 

jack