Cannot access the gateway router.

[canonpuppy]

First off, I wanted to thank people on the forum who helped me with my last problem.

Here’s what I have been puzzled about for the last a few days:

- I have a cable modem connected to a Linksys WIFI G router, IP addr: 192.168.1.1
- I have another router, Cisco 2514, connected to an internal network: 10.0.0.0 and the Linksys router
- Between the two routers is the DMZ: 192.168.1.0

I can ping the Linksys router (192.168.1.1) from computers in the 192.168.1.0 network and from within the Cisco router.
Also, I can ping any other computers in 192.168.1.0 network from 10.0.0.0 network but the Linksys (192.168.1.1) router. Therefore, the 10.0.0.0 net work cannot access the Internet.

Could anyone shed some light on what the problem might be? I would really appreciate!

Chuck

 

[ChrisAC]

Does the Linksys router have a route to the 10.0.0.0 network via the Cisco router?

Chris.


**********************
Chris Andrew, CCNA, CCSA
chris@iproute.co.uk
**********************

 

[canonpuppy]

Chris, thanks for the reply. No, the Linksys is setup as a gateway, not a router. Correct me if I am wrong: even if it had a route to the 10.0.0.0, it would be going the other direction.

Here is the topology again:

= The Linksys is on the Internet.
= The Cisco is behind the Linksys
= The 10.0.0.0 network is behind the Cisco
= The 192.168.1.0 network is between those two routers
= The Linksys is on the same network (192.168.1.0)
= From any computers in the 192.168.1.0 network, I can ping the Linksys router.
= From behind the Cisco (10.0.0.0), I can ping any other computers in the same network as the Linksys, but the Linksys router. Drives me nuts!
= Nothing is blocking ICMP protocol.

Doesn't seem to make any sense to me.
Any ideas?
Thanks so much.

 

[ChrisAC]

When a device from the 10.0.0.0 network sends a ping to the Linksys the Linksys will see packets from 10.0.0.x. How can it send echo replies to an address that it doesn't know where it is. If it just has a default gateway (the cable modem)then it will just send the packets out to that address, not to the 10.0.0.0 network.

The Linksys would need to know that it can reach the 10.0.0.0 network via the Cisco routers address.

Cable modem
|
Linksys router
|
192.168.1.0 net
|
Cisco router
|
10.0.0.0 net

So, the Cisco router can see both the 10.0.0.0 network and the 192.168.1.0 network. The Linksys can see the internet and the 192.168.1.0 network, BUT NOT the 10.0.0.0 network (because it doesn't have a route to it).

Chris.


**********************
Chris Andrew, CCNA, CCSA
chris@iproute.co.uk
**********************

 

[canonpuppy]

Chris, you're absolutely right about the route in the Linksys. I added a static route in the Linksys and now I am able to ping it from the 10.0.0.0 network. Thanks so much!!!

Here is a quick question:
Is there a way, or if it's possible, for 10.0.0.0 network computers to access the Internet without using a multi-homed proxy server?

Problem I am having for the 10.0.0.0 network now is:
If I use the Cisco router (10.0.0.1) as default gateway, the Web quest is routed to the 192.168.1.0 network, not to the Linksys router which is connected to the Internet;
If I use the Linksys (192.168.1.1) as the default gateway, the traffic wouldn't even get through the Cisco router to the default gateway...

Thanks a bunch in advance.

 

[ChrisAC]

Yes. Put a default route on the Cisco router that point's at the Linksys. So, when a client on the 10.0.0.0 tried to go to say

http://www.tek-tips.com

it will connect to 216.45.19.33. As the client won't have a route for this address it will forward the packets to the Cisco router. The router won't have a route for it either and so it will then forward to it's default gateway, the Linksys. As the Linksys has internet connectivity via the cable modem the traffic from the client will be forwarded to it's destination in the same manner.

At the moment the Cisco only knows about the 192.168.1.0 and 10.0.0.0 networks. If the packets that it receives aren't for either of these two networks then they will be dropped. If it has a default gateway then they will be forwarded to this address.

Chris.


**********************
Chris Andrew, CCNA, CCSA
chris@iproute.co.uk
**********************

 

[canonpuppy]

I added a route in the Cisco as you advised. Everything is working now. Just want to thank you for all your help!