NAT and Public addresses on LAN

[jnennemann]

I am novice in the router world, so any help would be greatly appreciated. I have a Soho 97 router and I would like to set it up so that some machines on the LAN can have public IP addresses but most others would have private IP numbers that are handled by NAT. What is the best course to take? Do I set up a sub-interface on the WAN port and assign it a public address and make it NAT outside?

[Georg Pauwen]

Hello,

you do not need another subinterface, just define an access list with the addresses you want to have translated, and those that are not in the access list will not be translated. Here is an example in which you have assigned a public IP address yo your WAN interface, and you have two sets of clients, one set with addresses from the range 192.168.1.0/24, and the second set with public addresses from the range 212.136.1.0/29. You need to assign a secondary address to your LAN interface, in order to cover both ranges:

interface Ethernet0

ip address 212.136.1.1 255.255.255.248

ip address 192.168.1.1 255.255.255.0

ip nat inside

!

interface dialer 1

ip address negotiated

or

ip address dhcp

!

ip nat outside

!

access-list 1 permit 192.168.0

!

ip nat inside source list 1 interface dialer 1 overload

Let me know if this is not working.

Regards,

Georg