Subject: FIN+ACK? for ESTABLISHED to CLOSE WAIT
To: None <tech-net@NetBSD.ORG>
From: Tony Tam <ttam@nortel.ca>
List: tech-net
Date: 11/25/1997 16:40:00
For those familiar with the state machine:

It appears to me that to transition from ESTABLISHED to CLOSE_WAIT in 
tcp_input.c, you need a FIN AND AN ACK; whereas the state machine shows only 
a FIN.  If you don't have an ACK it drops the packet and it never reaches 
FIN processing.  Does anyone know why this is the case?

Thanks,
Tony