TCP Teardown

[nebruin]

I had a quick question. With TCP teardown I know you have a four way hand shake, FIN -> FIN,ACK -> FIN -> FIN,ACK. I'm having trouble with a particular issue with a program reporting that the peer is resetting the connection. I went and used ethereal to grab a packet capture, and followed the socket along, and everytime it finishes with the standard 4 way handshake, but then after the handshake is done, it sends a reset packet (the peer does). I also looked at some other programs that were working, and they did the same thing, they sent a RST at the end of the 4 way handshake. Everything I've seen on the web says that there is only a 4 way handshake, but I wanted to double check to see if anyone had seen this sort of thing before, and if it was normal to see a RST at the end of a 4 way teardown.

Thanks for any help.

-Nebruin

 

[Darkstar850]

No. If you are seeing a RST packet, either the peer sending it sees a problem with the connection, or is not seeing traffic to keep the session alive. A RST is one side forcibly disconnecting a TCP session.