freebsd security - May 2007 - have anyone configured "synproxy state" beforce (Sorry for the previouly base64 encode mail caused by M$ outlook)

high everyone,( in pariticular Max :-))
 The configuration line in my pf.conf is:
 pass in quick on lo0 proto tcp from any to any port 21 flags S/SA synproxy 
state

 But:
 the connection is established, but the control did not seams to pass to the 
ftpd
Sincerely yours
Zhouyi Zhou