Robert LeBlanc a écrit :
the FTP protocol contains the source IP and port,
The _destination_ address and port.
which wouldn't make sense since it is a private address. At least that is what I understand of the FTP protocol. Are there any other protocols that have issues like this that I'm not aware of?
You can have an idea by looking at the available conntrack/NAT helper modules (ip_conntrack_* and ip_nat_*) for the Linux kernel : IRC DCC (file transfer and peer to peer communication with an IRC client), TFTP, PPTP, some communication/multimedia/peer to peer protocols such as H.323/Netmeeting, RTSP, SIP, MSN Messenger, DirectX, MMS (Microsoft Streaming Media), Talk...
