Unable to connect to Cisco internal resources with WRT54G Linksys Router

[jsiow]

I have a user who said that he's unable to connect to Cisco network in this way (Cable Modem <-- WRT54G <-- 831 Router <-- Laptop) but able to when he is without the WRT54G Linksys router. Has anyone encountered this before ?

What firmare version or FireWall settings, port forwarding settings on the Linksys router need to be looked at? Any help will be much appreciated.

[a.kiprawih]

Is the WRT54G brand new from ther box?

A quick check:

1. Check physical/cabling connectivity on the WRT54G to cable modem and Cisco 831 router. Make sure the user connect the port marked as 'Internet' to the cable modem (internet) side using correct cable. For the router Cisco 831 router, connect to any port (1 to 4) using UTP cross-over cable. Can the user see any active LED light on the router port?

2. Configuration

My assumption the reason why the router works without WRT54G was the configuration, where router is able to get IP/DHCP from ISP as the Ethernet interface facing the cable modem is set to obtain IP Address automatically.

So, when the Linksys box comes in, it need to be configured as the interface facing the router will carry different IP address (either static or DHCP). Either way works.

- Login to the Linksys via web browser (default IP is 192.168.1.1). Your PC must be configured with any 192.168.1.x with netmask 255.255.255.0.

Username: , Password: admin

- Go to SETUP tab. Check the Internet Connection Type. Default is DHCP (leave this). ISP will assign DHCP IP for this box. Or choose PPoE if you used this. Make sure account's username & password is correct

- Go to Network Setup. Note that default IP is 192.168.1.1 with subnet mask 255.255.255.0

DHCP is enabled by default for easy client connectivity. The default DHCP IP range start from 192.168.1.100, with a total of 50 IP Addresses. But this can be changed as required. Do not used 192.168.1.1.

Else, if the use choose to use static IP (DHCP better than static) on the Cisco 831 router Ethernet interface facing the Linksys, assign any IP starting from 192.168.1.2 to 192.168.1.49. Use 255.255.255.0 as netmask, and 192.168.1.1 as default route (to internet).

Make sure the router has default/static route statement pointing to Linksys:

ip route 0.0.0.0 0.0.0.0 192.168.1.1

More details:

http://www.linksys.com/servlet/Satellite?c=L_Product_C2&childpagename=US%2FLayout&cid=1115416825557&pagename=Linksys%2FCommon%2FVisitorWrapper

Hope this helps. Pls rate any useful post(s).

AK