[Samba] LAN and public IP

[Mihamina (R12y) Rakotomandimby]

Hi,
I am running Debian (Sid) and Samba 3.
My computer which intends to be only a SMB client is on a LAN (192.168.2.0/24)
We have a gateway to internet and it's public IP address is 81.56.120.7.
When I launch smbtree in order to "scan" existing SMB shares over the _LAN_ :


 mihamina at mihadev:~$ smbtree
 Password:
 MAINET
        \\SOPHIE                        SOPHIE
 timeout connecting to 81.56.120.7:445
 timeout connecting to 81.56.120.7:139
 Error connecting to 81.56.120.7 (Operation already in progress)
 cli_start_connection: failed to connect to SOPHIE<20> (81.56.120.7)
        \\PROPRI-EF83076E
 timeout connecting to 81.56.120.7:445
 timeout connecting to 81.56.120.7:139
 Error connecting to 81.56.120.7 (Operation already in progress)
 cli_start_connection: failed to connect to PROPRI-EF83076E<20>  
 (81.56.120.7)
        \\PROMETHEE
 timeout connecting to 81.56.120.7:445
 timeout connecting to 81.56.120.7:139
 Error connecting to 81.56.120.7 (Operation already in progress)
 cli_start_connection: failed to connect to PROMETHEE<20> (81.56.120.7)

Yep, my computer, on the LAN goes out and then tries to connect to the piblic 
IP of our gateway!

When I FTP or SSH any LAN computer, there's no outgoing route. A traceroute to 
a LAN IP address directly brings to the target computer. my routing 
tables "route" shows 192.168.2.x are not routed to the gateway.

What couls be the problem?