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Hello everybody, I have what is probably a pretty simple problem, I understand what the problem is, but am unsure as to the best way to resolve it. My goal: ...
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  1. #1
    Just Joined!
    Join Date
    Sep 2013
    Posts
    1

    dhcpd/dns - clients cant' resolve


    Hello everybody,

    I have what is probably a pretty simple problem, I understand what the problem is, but am unsure as to the best way to resolve it.

    My goal:

    I have a CentOS server with two NICs, one gets internet connection, the other hands out DHCP - so I want my server to effectively act as a router (like a DLINK or Linksys that one might use in their home).

    My current setup:

    Comcast modem --> router (handing out addresses, on 10.0.1.0 subnet via DHCP) --> CentOS server (and other clients) [also hands out addresses on 192.168.0.0 subnet via DHCP] --> other clients

    My setup after I get all of this worked out:

    Comcast modem --> CentOS server (handing out addresses on 192.168.0.0 subnet via DHCP --> all other clients

    My problem is that, in my current setup, the terminal clients, that is the ones at the very end of the chain, are unable to connect to the internet, they receive addresses from dhcpd running on the CentOS server just fine, they just can't see the outside world.

    The obvious problem is that I have the CentOS server as the DNS server for clients, and the CentOS has no name server running on it and I need to have one running on it. I don't need the name server to be authoritative for any domains (well, in the future it will be, as I want to run my own DNS), I just need it to be able to execute lookup queries and return addresses to the terminal clients. So how can I most easily do this? Would this be setting up BIND in "caching mode"?

    I have noticed that my Airport Extreme is listening on port 53, so it has to be doing something similar to what I am needing.

    Would somebody mind pointing me in the right direction? I would be eternally grateful!

    Here's my dhcpd.conf, just for fun:

    Code:
    ddns-update-style interim;
    authoritative;
    log-facility local7;
    default-lease-time 600;
    max-lease-time 7200;
    option subnet-mask 255.255.255.0;
    option broadcast-address 192.168.0.255;
    option routers 192.168.0.1;
    option domain-name-servers 192.168.0.1;
    option domain-name "mydomain";  <--I do have this filled in with the FQDN of my server
    subnet 192.168.0.0 netmask 255.255.255.0 {
     range 192.168.0.50 192.168.0.100;
    }
    Thank you very much!

  2. #2
    Linux User
    Join Date
    Dec 2011
    Location
    Turtle Island West
    Posts
    362
    I'm no network guru, but ...
    Wouldn't you set the DNS servers on the Centos server to the same ones that the modem uses?

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