Hello, After a few pairs of HTTP Get and Response, actually for different clients to retrieve data, over the same persistent upstream connection, Squid(3.1.11) may send one RST+ACK, following by a few RST's with the same sequence number as RST+ACK. In some other cases, Squid gracefully closes the upstream connection by initiating a FIN+ACK packet. I guess Squid has some management procedure to distinguish these cases... then what are the approaches? Thanks, Kaiwang