Map external IP as internal IP?

In article , Joe wrote: :What I want to do is to map an external IP to a local IP. :So, all the traffic to that external IP will goes directly to the local :IP... :Can I set that?

It depends on the platform and software release. It also depends on whether this traffic to the external IP address originates externally or internally.

For example on the PIX series with 6.x software or before, you cannot configure the PIX in such a way that you can have an inside host send a packet addressed to the external IP of something "inside" the PIX and have the PIX translate the external IP to the internal IP and have the PIX then send the packet back through the inside interface that it originally came from. PIX up through 6.x is designed to absolutely always prevent that from happening. [The various workarounds depend upon the PIX model in use, the software revision, and whether you have an internal or external router that is 802.1Q VLAN compatible.]

Thanks for reply.

The traffic to that external IP would be originates internally...

Client A---Internet | Firewall | Router-----Client B | Server

Like that, Client A and B would be a laptop and need to connect to that global IP(Server)... The external IP would be that "server", with NAT

I want to do that so, Client B's traffic no need to go out of the router but directly to "server".

The router is cisco 1800 series... Can I do that? and please give some sample configuration..

thanks.

Hi,

Do you already use NAT on the router or the firewall?

Cheers

Matt

yes, both the firewall and router do have NAT specific port to that server.

thanks.

Hi,

Ok, well I can post two lines, one for a router and one for a PIX for port mapping. If thats no good you will have to post your configs so we can see whats going on.

PIX -

static (inside,outside) tcp smtp smtp netmask

smtp being the port and tcp being the protocol, you will have to adjust to what port you require.

You will also have to modify your access list to allow in what you require.

Router -

ip nat inside source static tcp 25 25 extendable

Cheers

Matt