PIX on SOHO network config

[ROBERT CROOKS]

I just bought a PIX 501 for use at my home, and am having trouble understanding how I can use some P2P software correctly.

I have a PPPoE connection, and would like to foreward ports 411 and 412 to my PC, address 192.168.100.25.

Everything works well until I open up the ports on the outside interface to the inside. I always have to create a translation for my PC, but I don't have an extra public IP at my disposal for this. Could someone explain to me how to do it? How can I use NAT if the outside interface is always changing? I can't see how to code it, or visualize it either! My Linksys router was so easy compared to this.

Any help would be appreciated.

Thanks

[fmeetz]

If I got this right, your PIX outside interface is being assigned an IP address dynamically and you would like to use that address for NAT. Well this is easily configured. The DHCP learnt IP address can be used as the PAT global address. The only restriction is that you'll be configuring PAT. Please refer to:

http://www.cisco.com/univercd/cc/td/doc/product/iaabu/pix/pix_sw/v_62/config/pixclnt.htm#1031778 (under section Using the PIX Firewall DHCP Client)

Also refer to the section on global command: http://www.cisco.com/univercd/cc/td/doc/product/iaabu/pix/pix_62/cmdref/gl.htm

The following documents might help too:

Cisco Secure PIX Firewall Frequently Asked Questions

http://www.cisco.com/warp/public/110/pixfaq.shtml

Configuring and Troubleshooting the Cisco Secure PIX Firewall with a Single Internal Network:

http://www.cisco.com/warp/customer/110/single-net.shtml

"Using NAT and PAT Statements on the Cisco Secure PIX Firewall":

http://www.cisco.com/warp/customer/110/19.html

Documentation for CiscoSecure PIX Firewall

http://www.cisco.com/univercd/cc/td/doc/product/iaabu/pix/pix_sw/index.htm

Cisco Secure PIX Firewall Command References

http://www.cisco.com/warp/customer/110/pix_command_ref.shtml