How do I share an internet connection across a WAN? (i.e. consolidated internet))
Posted on 2011-09-07
Ok, I have four sites connected via a Wide Area Network.
One site acts as the "hub" site, and the other three all connect to this site. The cisco routers that terminate the ATM circuits are using eigrp to handle routing of traffic from one site to the other.
Here is the network info.
Main site is 172.16.0.0/20
Site 1 is 172.16.32.0/20
Site 2 is 172.16.48.0/20
Site 3 is 172.16.64.0/20
Edited to add*
The ATM Circuits are on the 192.168.254.0/30 network
The Main site has 3 VC's
The Branch sites are:
Site 1: 192.168.254.4
Site 2: 192.168.254.2
Site 3 192.168.254.8
So the main site's interface ATM1/0.10 (192.168.254.1) connects to site 2's interface ATM1/0.10 (192.168.254.2)
and so on for the other sites.
Right now each site has their own internet connection. The WAN router is the default gateway for each site, and there is a static route pointing to the firewall for that site.
So the Main site router has the local IP address 172.16.1.1, and the Firewall for that site is 172.16.1.5.
On the router the following command is given to route internet bound traffic to the firewall.
ip route 0.0.0.0 0.0.0.0 172.16.1.5
Each site is configured similarly.
Recently we upgraded our bandwidth at the main site to a full DS3 with the intention of sharing this internet connection with the other sites.
This is where I am running into some issues...
I have tried changing the static route on the other WAN routers to point to the main site firewall rather than each site's firewall, but this doesn't work.
I tried setting the static route on the branch sites to point to the main site WAN router (using both the 172.16.1.1 address as well as its ATM interface IP)
I also tried removing the static route to see if eigrp would actually route things for me.
None of these have worked.
I am not a router expert but I can't figure out why changing the static route doesn't work since the branch site routers "know" how to get to those other addresses (this was supposed to be configured by the provider when they installed the WAN, but the DS3 was delayed, so we setup the static routes as a temporary fix)
Also, I can post more information, including my current configs on the routers if that would help.