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I have an ADSL router that is connected to my ISP. The router gets his settings automatically. Whenever the assigned IP address changes it updated the dns entry for my ...
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  1. #21
    Linux User Allblack's Avatar
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    I have an ADSL router that is connected to my ISP. The router gets his settings automatically. Whenever the assigned IP address changes it updated the dns entry for my domain name on the ISPs dns servers.

    I have opened port 80 on my router and it points to the static ip address of my FreeBSD box ( the webserver)

    My other machine is running XP and Linux and it does not matter which one I use, it won't work.

    This machine gets an IP from the routers in-built DHCP function. It does not make a difference when I assign a static address. I cannot get to it when I use a browser on the webserver either.

    I don't run a local dns server. I don't have the XP set up as a part of domain so there is no internal defryn.com domain.

    Hope this helps

  2. #22
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    OK, then I get it. Since you're using a hardware router, it can't be fixed either. I was hoping that you were using a Linux box as router; then it would be possible to fix it.

    The thing is that your FQDN points at the IP address that the router uses. When you try to browse to your BSD server in your LAN, your browser contacts the router, which forwards the packet to the BSD box. Unfortunately, the router only changes the destination address of the packet, not the source address. Then, when the BSD box responds to the packet, it sends the reply to the source address of the SYN packet, which is of course the computer that you're running the browser on. Here the error comes: the browser expects a reply from the router (since that's where it sent the SYN packet), and when it receives something from the BSD box, it has no idea what context that packet would belong to, and thus silently discards it.
    If you had a Linux router, you would be able to make the router change both the destination _and_ source address of the SYN packet, so that the BSD box would have responded to the router, which in turn would have redirected the response packet back to the browser, with the "correct" source address. Unfortunately, I don't think that that's possible on a hardware router.

    So the consensus is that on your local LAN, you'll simply have to connect to the BSD server using either IP address or any alias you care to enter for it in your /etc/hosts. Or install a local DNS server that could alias it for you (which I don't think that you need in your case, though). Or use a Linux router instead.

  3. #23
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    hi,

    i'm assuming in this case the BSD box and the local machine are connected through the router...so in that case if the bsd box does send a reply it will have to send it to the router and the router will have to redirect it to the local machine right? and if the router does redirect it back to the local machine doesnt it change the src and destination addresses back?

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  5. #24
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    There is a difference. These hardware routers with several ethernet connectors in essence consist of two parts: a switch and a router. Therefore, only packets that are headed for the router are actually passed to the router, since the switch part won't send packets intended for other local ethernet nodes to it. Therefore, the packet isn't really forwared, it's rather repeated.

  6. #25
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    oh ok...that explains it...cool...thanks for the info.....

  7. #26
    Linux User Allblack's Avatar
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    Thanks.

    I guess we came to the end of this post then. I will create an entry in my hosts file as this is the simplest solution had this stage.

    You have been most helpful.

    Cheers

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