A BIO IP Administrator is troubleshooting a slow web application. A packet capture shows that some of the packets coming from a window size of zero. A packet capture shows that som a window size of ze

TCP connection teardown initiated by the client uses a FIN flag in the TCP header, not a window size of zero.

A server-initiated connection close is signaled by a FIN or RST flag, not by advertising a zero window size.

In TCP flow control, the window size field is advertised by the sender of a packet to inform the opposite endpoint how much receive buffer space is available. If packets originating from the server carry a window size of zero, the server is signaling to the client that its TCP receive buffer is exhausted and the client must pause transmission until the server sends a window update with a non-zero value. This is a normal TCP flow control mechanism, not a connection termination signal.

If the client were temporarily unable to receive data, it would be the client sending packets with a window size of zero, not the server; the question states the zero-window packets are coming from the server side.