Wireshark · Wireshark-users: Re: [Wireshark-users] Retransmission because of no ACK from user

[Sake Blok <sake@xxxxxxxxxx>]

On 16 jan 2011, at 06:46, vincent paul wrote:

> I am looking at one trace with retransmissions from server because user's side did not send ACK for packets it received from server.  Is there any reason why user's side does not send out ACK.

Well, finding the reason for irregular behavior is the whole point of packet analysis. You have a starting point that you don't see ACKs from the user t the point where you made the traces. From this point onwards, you have to start thinking about what could have gone wrong.

1) Do you see any traffic from the client after the point where retransmissions start? If not, the client probably disconnected in the middle of the session. Or an intermediate link broke down.

2) If there are packets from the client later on, there might have been a link problem for a while, or maybe a saturated link etc.

You might have to capture closer to the client to determine where the problem starts. Usually you would make traces both at the client and the server side and move them towards one-another to find the spot where things go bad.

Good luck!


Sake