[Samba] samba in NATed network

[Eric Lopez]

We have about 300 users distributed on different vlans using private ip 
network spaces,  and sharing one single public IP when going out to the 
Internet. Our samba (3.0.24) server has a pulbic IP and is running as a 
primary domain controller. All clients receive Sambas's public IP as 
their WINS server.   I am able to join the domain but samba stops 
responding sporadically.  Looking at the logs,   I found two things:
First  on samba/log.smb:

  oscar01 (4.5.6.7) closed connection to service netlogon
[2008/04/30 11:55:12, 0] lib/util_sock.c:get_peer_addr(1229)
  getpeername failed. Error was Transport endpoint is not connected
[2008/04/30 11:55:12, 0] lib/util_sock.c:write_data(562)
  write_data: write failure in writing to client 4.5.6.7. Error 
Connection reset by peer
[2008/04/30 11:55:12, 0] lib/util_sock.c:send_smb(769)
  Error writing 4 bytes to client. -1. (Connection reset by peer)

Searching on google It seems that this is caused by smb ports=445 139  
and can be fixed by setting it to smb ports=445. I already made this change.

Second on samba/log.nmbd

[2008/04/30 14:25:31, 1] libsmb/cliconnect.c:cli_connect(1369)
  Error connecting to 4.5.6.7 (Operation already in progress)
[2008/04/30 14:40:40, 1] lib/util_sock.c:open_socket_out(896)
  timeout connecting to 4.5.6.7:139

Here it looks like samba is trying to initiate a connection using the 
NAT/firewall public IP, which is never going to work since there's no 
port forwarding in place. Which makes me wonder, is it possible to run 
samba on a NATed network??
Thank you in advance for your input,
eric.