I have two freebsd servers: one with freebsd6.2 and new freebsd7.0.
I use ipnat for nat and ipfw (with dynamic rules accepting returning
traffic) as firewall.
Lately i noticed strange problem with FTP.
When i try to connect to remote FTP server from my client and
i use passive mode after logging in and typing "ls -la"
i receive data (file listing), files are diplayed but the connection is
instatly broken.

What could be wrong ? Why ?