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Router or Modem Settings?

Discussion in 'Networking' started by Hagioscope, Feb 26, 2013.

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  1. Hagioscope

    Hagioscope Thread Starter

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    We have a Comcast business class cable modem with a static IP address. There are two devices hardwired to it; a server and a Linksys WRT610N

    The server is hardwired to it with port forwarding set for ports 21, 80 and 5900. It works perfectly and can be reached as intended by the outside world but not by our own network.

    Our Linksys WRT610N is hardwired to the modem. All computers on the wireless network see each other and can access the internet perfectly.

    So all seems well enough.

    BUT, no computer on our network can reach our server. Using the domain name or VNC connections from inside our system results in time outs and no connection.

    Comcast support says it must be an issue in our router settings but I'm at a loss as to what that would be.
     
  2. TerryNet

    TerryNet Moderator

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    So, the "business class cable modem" is a modem/router combination unit with the Linksys router daisy-chained to it? You may be able to access the server by IP address from the Linksys's LAN. Do you really want the Linksys as a second router? For accessing the server it would be better to use the Linksys as an ethernet switch and wireless access point.
     
  3. Hagioscope

    Hagioscope Thread Starter

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    Hmm, sometimes the obvious sure can hide. I went with the modem's directions for setting up a server and really hadn't given a lot of thought to the fact that we're daisy chaining. It would make much more sense just to pass everything through to the Linksys.

    It still defies my logic that it fails as it is, but rather than fight it further I'll pursue that.

    Thanks for your help (that I suspect will work)
     
  4. Couriant

    Couriant Trusted Advisor

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    Just out of curiosity, what modem did they provide?
     
  5. Hagioscope

    Hagioscope Thread Starter

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    I'm working remotely using VNC at present but the software claims it's from SMC Networks.

    I was failing to configure it remotely and can't try TerryNet's suggestion until I can get to the location but I'm hopeful.
     
  6. TerryNet

    TerryNet Moderator

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    If you decide instead to keep the modem/router as is, you can do the following with the Linksys.

    JohnWill's procedure (Aug. 30, 2008) for configuring a secondary router as a switch and, optionally, wireless access point follows.

    Connecting two (or more) SOHO broadband routers together.

    Note: The "primary" router can be an actual router, a software gateway like Microsoft Internet Connection Sharing, or a server connection that has the capability to supply more than one IP address using DHCP server capability. No changes are made to the primary "router" configuration.

    Configure the IP address of the secondary router(s) to be in the same subnet as the primary router, but out of the range of the DHCP server in the primary router. For instance DHCP server addresses 192.168.0.2 through 192.168.0.100, I'd assign the secondary router 192.168.0.254 as it's IP address, 192.168.0.253 for another router, etc.

    Note: Do this first, as you will have to reboot the computer to connect to the router again for the remaining changes.

    Disable the DHCP server in the secondary router.

    Setup the wireless section just the way you would if it was the primary router, channels, encryption, etc.

    Connect from the primary router's LAN port to one of the LAN ports on the secondary router. If there is no uplink port and neither of the routers have auto-sensing ports, use a cross-over cable. [You will not need a cross-over cable if one of the "routers" is a computer.] Leave the WAN port unconnected!

    This procedure bypasses the routing function (NAT layer) and configures the router as a switch (or wireless access point for wireless routers).

    For reference, here's a link to a Typical example config using a Netgear router
     
  7. Couriant

    Couriant Trusted Advisor

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    Is the router the one with the Static IP? I'm just curious as I work for an ISP and the SMC modems we do are configured with the Static IP.
     
  8. Hagioscope

    Hagioscope Thread Starter

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    Thanks - Today I'm in the process of weighing options. The Linksys router has its ports all occupied. That can be resolved but if I leave things as is and make it a switch there's far less disruption.

    Your helpful suggestions are appreicated.

    Probably a moot point but my brain just can't understand why it's all working except for being able to reach our own domain name on the modem since we can get everything else on the internet.
     
  9. Hagioscope

    Hagioscope Thread Starter

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    The static IP comes into the modem where I have port forwarding passing ports 21, 80 and 5900 to the server. Everything else goes on to the Lnksys router. I've never touched anything on the router so it remains on its 192.168.1.1, etc.

    I've done many setups with a modem to a single router but this is the first time I've not sent everything to the router for forwarding, etc.
     
  10. TerryNet

    TerryNet Moderator

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    By "domain name" do you mean URL as if you are accessing from a remote location? If so, that depends on whether the router does "loopback." Some do and some don't and the only way I know to find out is to try it.
     
  11. Hagioscope

    Hagioscope Thread Starter

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    Loopback sounds like what we must be doing. I'm not familiar with it so I'll have to start doing some research to learn.

    We can reach the server perfectly from remote locations. I'm on it now using VNC. From within the network it's the only unreachable domain.

    BTW, it's my first experience here and I'm impressed. I know some other folks that will like this site.
     
  12. TerryNet

    TerryNet Moderator

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    If it's loopback (or rather, the router not doing that) giving the problem then reconfiguring the Linksys as switch and WAP will not help. You probably can access the server by its (private) IP address. If so, one workaround is to add a line to the Hosts file (in each computer) to define it.

    If you bridged the modem/router to act as a modem only and connected the server to the Linksys (adding an ethernet switch to give the additional port needed) then the access would depend on whether the Linksys does loopback.
     
  13. Couriant

    Couriant Trusted Advisor

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    Or perhaps turn off DHCP and bridge the Linksys router to essentially make it a switch so it will be on the same network as the server?
     
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