LinuxQuestions.org - Strange problem with ProFTPd

Hello,
I've a strange problem with proftpd.
It's on debian squeeze, proftpd 1.3.3a-6

I use postgresql mod for auth and it's behind a NAT router (pfSense).
here is a part of my config file :

Code:

TimeoutNoTransfer                600

TimeoutStalled                        600

TimeoutIdle                        1200



PassivePorts                    60000 65534

Umask                                022  022



AllowOverwrite                        on

UseSendFile                        on



MasqueradeAddress monhostname.com

The error is :
After every file I upload I'm disconnected from the server

Code:

ftp> put billets.pdf

local: billets.pdf remote: billets.pdf

229 Entering Extended Passive Mode (|||64635|)

150 Opening BINARY mode data connection for billets.pdf

100% |***********************************************************************************************************************| 28953      111.33 MiB/s    00:00 ETA

421 Service not available, remote server has closed connection.

28953 bytes sent in 00:00 (166.11 KiB/s)

ftp>

Nothing strange in logs

Code:

Fri Mar 11 14:03:27 2011 0 xxxxxxxxx 28953 /mnt/data/billets.pdf a _ d r monuser ftp 0 * c

Can you help me ?
thanks you !