Routing a Public IP Address across a GRE Tunnel

GSims · ‎12-29-2009

Currently where I work at has a couple of public IP Addresses that I can use. However my home internet connection does not have a public static IP Address for the internet connection. Currently I have a GRE Tunnel setup with a couple of IOS routers to allow for me to communicate with a couple of my clients one of which is at my work with the spare IP Addresses. The question that I have is, can I use a couple of the spare public IP Addresses that work has and route/nat them across to a couple of servers that I have at my house? Just trying to take advantage of the spare IP Addresses that are not doing anything and setup a couple servers to try doing web site development and setup an email server. Any configuration examples or at least pointed in the right direction would be greatly appreciated.

Thanks in advance,

Gordon

Jon Marshall · ‎12-30-2009

GSims@SimpleConnections.net
Currently where I work at has a couple of public IP Addresses that I can use.  However my home internet connection does not have a public static IP Address for the internet connection.  Currently I have a GRE Tunnel setup with a couple of IOS routers to allow for me to communicate with a couple of my clients one of which is at my work with the spare IP Addresses.  The question that I have is, can I use a couple of the spare public IP Addresses that work has and route/nat them across to a couple of servers that I have at my house?  Just trying to take advantage of the spare IP Addresses that are not doing anything and setup a couple servers to try doing web site development and setup an email server.  Any configuration examples or at least pointed in the right direction would be greatly appreciated.
Thanks in advance,
Gordon

Gordon

A topology diagram might help.

I'm unclear as to what exactly you are trying to do. You have a GRE tunnel from your home ? to work - is that correct. And if you do why do you need to use public IPs. Where are you trying to access the servers from ?

Could you fill in the blanks.

Jon

GSims · ‎12-30-2009

Topology as follow:

1811 Cisco Router (work - Static IP with extra IP's)------Internet------(Home on a Dynamic IP) 2811 Cisco Router

| |

Client 1 (Static IP)------+ +--------Client 2 (Dynamic IP)

I have a GRE Tunnel between all the locations that is working fine. The Idea is that I only have a dynamic IP address at my home and at my home I have a couple of servers built, one for a web site and another for email. I would like to have access to them from the outside world without having to VPN in to get to them. Is there a way to use the Extra IP's from my work to be natted to a server that is at my home and to have it go out with that IP Address for Reverse DNS purposes.

Thanks again,

Gordon

Ricardo Prado Rueda · ‎12-30-2009

Hi Gordon,

If I understandy correctly the 1811 has some extra public addresses and it has connectivity to the remote servers through a GRE tunnel, right? You can very well apply NAT on the 1811, setting the tunnel interface as "ip nat inside" and the physical WAN interface as "ip nat outside". As long as there is the correct routing on the 1811 to reach the private addresses of the server this should work fine.

Regards,

Rick.