NAT/PAT on Cisco router 1760

[Glloq007]

It's a Router 1760 connected to Internet through ADSL connection.
Behind this router, I have a Linux VPN. I'd like to terminate my VPN connection to the 44444 port from internet.
That means the router should act as transparent mode.
Each incoming ports must be forwarded to the Linux VPN/Firewall.

From router point of view, do I need a special IOS ?

 

[KiscoKid]

Based on what you've described, I just ran that through Cisco's software advisor and they recommending feature packet IP/ADSL Plus IPSEC 56 as a minimum from the 12.2T train.

Specifically it recommends either:
12.2(15)ZL1 (64MB DRAM/16MB FLash)
12.2(13)ZH2 (64MB DRAM/16MB FLash)
12.2(15)T17 (48MB DRAM/16MB FLash)

Of course if you need more features than you've described here, then this image may not be right for you.

Hope this helps