Is this a NAT issue?
Posted on 2007-03-23
I know there's someone here that can help me with this. I have a problem with a lab I'm trying to set up. Here's how I have it set up:
I have a Cisco 2600 router as my WAN router (connected to my ISP through a cable modem). The cable modem is connected to the fastethernet 0/0 port on my router.
The fastethernet 0/1 port on the router is connected to a pair of trunked Cisco 3512 switches. All ports on both switches are running on VLAN 2. There are 2 PCs and 1 server connected to ports on either of the 3512 switches.
The 2600 router has full connectivity to every device in my LAN and to the ISP default gateway. There's nothing this router can't ping on my LAN. I've also successfully pinged a few different DNS servers just to make sure my router can reach the internet. So the problem I'm having is definitely with the 2600 router.
My LAN IP scheme is 10.2.2.x 255.255.255.240. I have a static route on my router and is the following:
ip route 0.0.0.0 0.0.0.0 f0/0
(so I'm telling my router to forward packets with any IP and mask to f0/0 which takes them to the internet.)
I also put a static route in (which I'm not sure is necessary), which was:
ip route 10.2.2.0 255.255.255.240 f0/1
The PC I'm on to test the network is connected to one of the 3500 switches. The PC I'm on can also ping all devices on my LAN. The PC can also ping the WAN interface (f0/0) on the 2600 router.
Problem is, I can't ping my ISP default gateway from my PC!! As a result, I have no internet access from my PCs. The ONLY device that can communicate with the internet is my 2600 router.
I believe the problem has something to do with NAT. I was not able to find any NAT settings on my 2600 router. A few questions:
-Is my 2600 router capable of acting as my edge router? How can I determine this?
-Do I need to configure NAT to get this setup to work?
-If the solution is not NAT, what could be the problem?