Can't use cable modem through wireless router
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Thread: Can't use cable modem through wireless router

  1. #1
    Junior Member
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    Can't use cable modem through wireless router

    Ok,
    I've just switched from ADSL Cable internet. My setup is as such:
    A cable modem attached to a D-Link DSL-604+ router. The router is basically acting like a switch, since I can't plug the cable modem into the rj-11 DSL jack. I called my cable ISP and got a second IP address allocated, which allows 2 computers to use the internet. Unfortunatly, this only works if the computers are connected to the router with cables. For some reason, wireless NICs can't access the internet, even though they can see the other computers on the network. Any ideas?

    Thanks in advance.

  2. #2
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    You assigned the two IP's to your two computers and set default gateways, and subnets that your ISP gave you to your wirless network adapter?

    Can you ping anything outside your network? like your ISP's DNS servers, or ISP's gateway?

    why not just spend $40 to get a regular router?
    =

  3. #3
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    Hey Hey,

    I'm trying to make sense of your post.. and I think I've got it figured out


    Scenerio:

    Router is a DSL router... configuration (based on what I've looked up)

    Built in DSL Modem.
    1 WAN interface (Because the modem is built in this is RJ-11 instead of RJ-45)
    4 LAN interfaces (4 Port Switch).
    802.1b Access Point

    2 Computers...

    Wireless NICs
    Wired NICs

    Cable Modem.
    1 Coax Connection (WAN)
    1 RJ-45 Connection (LAN)

    You have your modem and both computers plugged into your switch.. This works fine for accessing the internet.. Both machines need their own Public IPs because they are on the switch (it's like being directly connected to the Cable Modem)...

    Your router can't connect to the cable modem because it's WAN interface is RJ-11 (Because it's a DSL Router)... This is why you have it plugged into the switch portion and why it is functioning exactly as it's designed too.

    Your 802.1b AP (the wireless) is basically setup in the firmware... It takes wireless signals and sends them out the WAN port... It doesn't interact with the Switch... If you access another local IP Address the router portion knows that it's local and sends it out the switch... But as far as you are concerned the Wireless AP and the Wired Switch are seperate entities..

    Since the Wireless AP automatically uses the WAN interface... you need the WAN interface to be active... You can only have an active WAN interface if you use DSL.... You can see the local computers because the addresses are translated locally and pass from Wireless AP to Wired Switch....

    Everything is functioning exactly as it was designed to and is following networking protocols to a T.... You need a wireless router with an RJ-45 connection (or a built in Cable Modem) in order to wirelessly access your internet connection.

    Hopefully you understood all of that.

    Peace,
    HT
    IT Blog: .:Computer Defense:.
    PnCHd (Pronounced Pinched): Acronym - Point 'n Click Hacked. As in: "That website was pinched" or "The skiddie pinched my computer because I forgot to patch".

  4. #4
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    Hey,

    In response to Cheyanne, I'm trying to stay away from buying anymore hardware, if I can. My budget is fairly tight at the moment. Hehe, most people I've talked to about this have told me to quit being foolish and just buy another router.

    I can see from HTRegz's post that I'll have to be a little more thorough in my questions.

    Your analysis of my setup is correct, but I'm not sure about not being able to get it to work. Actually, I'm typing this on my laptop on the other side of the house from the router.

    I plugged my laptop into the router to get the IP/DNS information, and then manually applied these settings to my wireless connection. Basically, I've bridged the gap between the WAN and my LAN. Granted, I had to set the netmask to 255.255.224.0, and I'm sure this will cause problems down the road, but until I get my paycheque and get another router, it should do fine.

    I'm still a little fuzzy on the technologies employed here though, so correct me if I'm wrong in doing this. Will this adversly affect the network, or any other users? I'm not really worried about the ISP. They've assigned my an IP, and I don't think it will change before I get another router.

    BD

  5. #5
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    Hey Hey,

    So you're using the wireless as strictly an access point... It makes sense... Just not something I considered... blame it on lack of sleep on my end... I guess sometimes the simplest solution is the easiest..

    I've never really considered setting a static public IP address on a router and then using it to access the modem. It works.. just not in the intended way..

    As far as problems.. The only problem that I forsee is you probably won't be able to access your router's Web Management. Since you're only using it as a switch right now, that won't be that big of a deal....

    As far as spending money on the other router... Doesn't your Cable company charge you for the second IP?? I'd think that buying a different router (I know you said you're going that route.. but I'm trying to give you some justification)... anyways... wouldn't buying another router be cheaper than paying for the extra IP for however long you have it?

    Peace,
    HT
    IT Blog: .:Computer Defense:.
    PnCHd (Pronounced Pinched): Acronym - Point 'n Click Hacked. As in: "That website was pinched" or "The skiddie pinched my computer because I forgot to patch".

  6. #6
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    Feb 2003
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    Heya,
    Actually, we get 2 free IPs with our account. I was fully expecting to pay for the second as well. Unfortunately, the third computer won't be able to get internet, but that's really well and good. The other roomate can use my computer, since I'm up at all hours of the night.

    We're moving soon, the third computer's not coming with us, so I might not spend the money on another router. I wasn't really sure if it was appropriate to do this since it's, as you pointed out, not the intended way for the router/service to work. If it doesn't cause any problems though, I may as well save myself the money.

    As far as accessing the router's web config, the main computer sitting right next to the router has 2 nics in it. May as well set the second to 192.168.0.1 and throw another cable in there. Sounds like a lot of wires for a wireless network, eh? Hehe

    BD

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