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Problems setting up a static routing

Discussion in 'Cisco/Linksys Wireless Routers' started by grimalkin2, May 29, 2005.

  1. grimalkin2

    grimalkin2 Network Guru Member

    OK, so I'm rather clueless about networking, sorry if this is a stupid question.

    I have a WRT54G, running Alchemy firmware (needed WDS). I'm trying to set up a static route, redirecting one IP address to another. Sounds simple enough, right?

    I want packets sent from one of my machines (#1) to a particular IP address to instead go to another address, which is a machine I control (#2) that is running an extra ethernet interface on that address, with IP forwarding. This has been working fine while machine 2 has been on my LAN. But I've moved it to an outside office. So I changed my static routing table, entering the new target IP address in the Default Gateway field, and switching the Interface popup from "LAN & Wireless" to "WAN (Internet)".

    The problem is the new routing does not show up in the routing table, and does not seem to exist. In fact, no matter what I put in the fields, I don't seem to be able to create a static route using the WAN interface. I've tried everything reasonable for the Subnet Mask. Why would this be??? Is it a problem with the sveasoft firmware? I upgraded from Satori to Alchemy, but no change.

    If it matters, here's why I want to do this:

    I have a TiVo, and live in Canada. The TiVo service is not available in Canada. To get it to work, I have to run software (Simplicity) on another machine which pretends to be the TiVo mothership. When the TiVo box phones home (over ethernet), instead of talking to TiVo at 204.176.49.2, it needs to talk to my machine. I haven't hacked the TiVo itself, so at the moment at least I can't change the address it is trying to talk to. So I set up a static route on the router, turned on IP forwarding on machine 2, and everything was hunky-dory. But now that machine 2 is not on the LAN, I can't seem to make it work.

    Any ideas?

    Thanks,
    Bob
     
  2. grimalkin2

    grimalkin2 Network Guru Member

    Bump...

    Nobody has any ideas? This is a router; it's supposed to route! What am I misunderstanding? Is it a matter of gateway vs. RIP mode, or something like that?

    Bob
     
  3. Guyfromhe

    Guyfromhe Network Guru Member

    if your tryign to do this over the internet, it won't work, you'll need to setup a proxy on the lan and have that relay the packets to the remote server and then pass them back, you might be able to use a NAT trick to re-write the dest. address to be the address of the server on the internet then re-write it back on the way into the lan, i'll look into it and post results.
     
  4. grimalkin2

    grimalkin2 Network Guru Member

    OK, thanks, I figured it was something basic I was misunderstanding. Can you tell me why it won't work over the Internet, or point me to a networking info page that explains why? Naively, it seems to me I should be able to specify any address I want, including my remote machine, as the gateway for this routing. But clearly it doesn't work.
     
  5. Guyfromhe

    Guyfromhe Network Guru Member

    when you specify the IP of the gateway the IP isn't actually used and the packet isn't touched, what happens is the MAC destination address of the packet is set to the ARP response of the gateways IP, since you can't pass ARP traffic to the internet or even across routers you won't be able to get to that gateway...
    heres what happens.
    Tivo arps for gateway IP to get it's mac.
    No response.
    Tivo continues arping for that IP, and no data can be passed as it has no gateway to pass it through.

    What you need to do is re-write the destination IP of the packet to be the IP of the "tivo server" then re-write it back on the way back in just like NAT does but backwards...
     
  6. grimalkin2

    grimalkin2 Network Guru Member

    OK, thanks, I mostly understand that. Except when you say Tivo arps for gateway MAC address, you mean the router, right? Actually the router doesn't even seem to setup the route in the first place (doesn't show up in the routing table) - presumably because it can't find the gateway's MAC? What happened when I set it up the first time and tried to use it, before noticing that the route wasn't in the routing table, was that the Tivo actually talked to the Tivo mothership. (This was a bad thing - it then decided I didn't have a current account, and erased all its guide data!)

    Sounds like what I want to do is beyond the capablity of the router. Ah, well! I guess the smart thing to do is finally get around to hacking the Tivo; then I can get in and change the Tivo mothership address.

    Bob
     
  7. Guyfromhe

    Guyfromhe Network Guru Member

    if the tivo's gateway is the router than should be right...I don't know how it decides what to show in the routing table or not, I havn't tried playing with it much it's probably not working because the gateway address isn't on your local lan...

    if thats the case it wouldn't add it and send it to the default route which would go to the internet, why can't you keep your server on the local lan?
     
  8. grimalkin2

    grimalkin2 Network Guru Member

    Right, but I was confused because when creating a routing entry I am able to choose "WAN (Internet)" in the Interface popup. Given your description of how routing actually works, I guess I still don't understand how a WAN routing would work in the first place... or what the buit-in routes that show up in the routing table mean:

    Routing Table Entry List
    Destination LAN IP Subnet Mask Gateway Interface
    192.168.1.0 255.255.255.0 0.0.0.0 LAN & Wireless
    24.80.14.0 255.255.255.0 0.0.0.0 WAN (Internet)
    0.0.0.0 0.0.0.0 24.80.14.1 WAN (Internet)


    Oh, just a matter of convenience.
     
  9. Guyfromhe

    Guyfromhe Network Guru Member

    most people wouldn't use WAN routing, unless it's not connected to the internet but another network, or if you control the router next to your linksys box and thats linked to the internet...

    Destination LAN IP Subnet Mask Gateway Interface
    1. 192.168.1.0 255.255.255.0 0.0.0.0 LAN & Wireless
    2. 24.80.14.0 255.255.255.0 0.0.0.0 WAN (Internet)
    3. 0.0.0.0 0.0.0.0 24.80.14.1 WAN (Internet)

    1. route all traffic to 192.168.1.0/24 (192.168.1.0-192.168.1.255) through gateway 0.0.0.0 because this is local to the LAN and Wireless network it doesn't need a gateway so just send it where it's asking to go directly.

    2. route all traffic destined for 24.80.14.0/24 (same thing with the /24) though itself - this is probably your internet address which your machine is on on that network it should be able to communicate directly with any machine in the same 24.80.14.* range based on the netmask assigned.

    3. default gateway - anything that does't fit into 192.168.1.* or 24.80.14.* should be sent to 24.80.14.1's MAC address.

    hope that clears it up a bit..
     

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