Cascaded LAN - No internet access

Discussion in 'Networking Issues' started by lmaillot, Aug 6, 2006.

  1. lmaillot

    lmaillot LI Guru Member


    I'm using a WRT54G (ver 1.1 with latest linksys firmware) as internet gateway with subnet 192.168.1.x on the LAN. On the same LAN I've a casdaded router (CISCO 2500) with one Ethernet interface connected on the 192.168.1.x LAN and an other interface on 10.0.0.x subnet.

    My Linksys being on and the 2500 on, I've defined a static route on the linksys to reach the 10.0.0.x network from and a default route on the 2500 toward the linksys.

    Ok, well I can ping from any host on 10.0.0.x to any host on 192.168.1.x but I could not go on the internet from the 10.0.0.x subnet... (while it is working well from the 192.168.1.x)... ant idea ?

    It seems that linksys NAT doesn't work on source address not being on the LAN... does any one know how to fix this ?

  2. Toxic

    Toxic Administrator Staff Member

    does the Cisco 2500 support RIP? you could enable RIP on the linksys and the Cisco and they will setup routing accordingly.

    is the Cisco setup as a Router and not a Gateway?
  3. eric_stewart

    eric_stewart Super Moderator Staff Member Member

    I've seen this before with the Linksys WRV54G. It won't NAT source addresses other than those from its own "inside" network. I'm not sure if turning on RIP and turning on "router" mode vs. "gateway" mode will work. I suppose it will if router mode turns off NAT.

    Try Toxic's suggestion, but I have another that I know will work. Turn *on* NAT on the 2500. That way the packets going outbound from the network inside the Cisco 2500 will be NAT'd to the common, inside, subnet between your Linksys and the Cisco 2500.

  4. lmaillot

    lmaillot LI Guru Member

    Hi Eric / Toxic,

    Thank you for the advises.

    I thinks I will do nating from the CSICO 2500, to have all packets leaving from 10.0.0.x network with a 192.168.0.x address as I do not want to turn off gateway mode or NAT on the Linksys as I wan't my linksys to act as firewall.

    The same thing with RIP, I asume that if I turn it on it will stop the NAT and firewall on the linksys... My CISCO router act as router not gateway to the internet.
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