Setting up internet connection with Cisco 2600

[jalewellyn]

Hello,

I am just getting my feet wet with Cisco equipment and have setup a lab with two 3560 switches and a 2600 router. I am trying to get internet connectivity established on the router, but do not seem to be having any luck. I can pull an IP address via DHCP from my ISP and can confirm that routes are shown in the routing table on the router, but I cannot ping anything either by IP or by DNS. 

I have one test client connected to the router and have the router set to DHCP. It appears that DHCP dishes out IP information as it should; an IP address, default gateway, and DNS information from my ISP (I set import all on the router), but like the 2600, the client cannot ping either.

What am I missing here? I have read several guides, and all the commands provided seem to be correct, but I cannot get connected. Any help would be greatly appreciated. I have attached a copy of my running configuration as well as routing information from the 2600.

[Henrik Grankvist]

Hi

This is what's wrong:

ip route 0.0.0.0 0.0.0.0 10.10.20.1

It is pointing to your own interface on the inside, it needs to point to your ISPs IP address on your fa0/0 interface.

Something like this, depending on your ISPs IP address:

ip route 0.0.0.0.0 0.0.0.0 50.29.192.x

[jalewellyn]

Okay, I will give that a try. Initially, I had it set to the WAN interface itself (fa0/0 and that did not work), something like the following:

ip route 0.0.0.0.0 0.0.0.0 fa0/0

Let me give your suggestion a try! Thanks for the input.

[Henrik Grankvist · Accepted solution]

Hello again. I looked around on the internet and found that you can use this command:

ip route 0.0.0.0 0.0.0.0 dhcp

It should make it a lot easier.

Edit:

Try removing all the static default route commands. It should install a default route with administrative distance of 254 automatically, if one is provided by the ISP.

[jalewellyn]

Yep, setting the static route to DHCP did the job! I am curious as to why setting it to the WAN interface did not work, but nonetheless, this works like a charm. Thanks again for the help!

[Henrik Grankvist]

No problem and thank you for your rating!

A short explination why your "ip route 0.0.0.0 0.0.0.0 fa0/0" doesnt work:

It's because a fastethernet interface is a multiaccess interface, which means there could be multiple routers on that interface. With the command "ip route 0.0.0.0 0.0.0.0 fa0/0", it doesn't specify where to send it, so it has to rely on something called proxy arp, which for the most part not activated by your ISP.

It would work on a pont-to-point interface like a serial interface.