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  1. #1

    DNS question

    Hi people...
    Im having trouble configuring a DNS server behind a firewall (IPCOP) and maybe someone could help me here. I will descibre my configuration below.

    - My firewall has a valid ip number (public ip)
    - my internal net is 192.168.254.x
    - my DMZ is 192.168.0.x ... where my DNS server is

    My internal net is working fine using this DNS server, but when i try to hit this server from outside im getting problems. Lets say my domain is, when i try my all is ok (i can resolve), but when i try (or i cant resolve.

    my zone file is as follow:

    $TTL 86400
    @ IN SOA (
    2001122403 ; serial
    10800 ; refresh 3 hours
    3600 ; retry 1 hour
    3600 ; expire 1 hours
    36400 ; minimum 24 hours
    IN NS
    @ IN A
    IN MX 10

    mail IN A
    www IN A
    ftp IN A
    ns1 IN A
    IN MX 10

    I dont know if is right to set the ip in this zone file to a internal ip (i think it is). thanks to all to read my post.

  2. #2
    Linux Guru sarumont's Avatar
    Join Date
    Apr 2003

    Re: DNS question

    Quote Originally Posted by aralata
    I dont know if is right to set the ip in this zone file to a internal ip (i think it is). thanks to all to read my post.
    That's the problem...if an external server hits your NS, it will resolve the hostname to a 192.168.*.* address, which it can't find (or can find, but not properly). For this situation, they all need to point to the same IP (your public) and just have your gateway NAT based on port.
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  3. #3
    Just Joined!
    Join Date
    Jul 2005
    San Jose, CA
    As a side note, try ditching IPCOP and go with FirewallBuilder at Much better intuitive firewall. Then you can quickly set up the NAT'ing necessary with drag and drop and get logs of connections to the firewall that are failing... Very good logging to help you troubleshoot what rule has failed. Just an FYI.

  4. $spacer_open
  5. #4
    Linux Newbie
    Join Date
    Apr 2003
    Pontypridd, Wales
    Lets start with DNS:

    The DNS data needs to put on the DNS server that serves your domain.

    For example, I use everydns, who provide me with DNS services. Using the web interface I point the domain at my world facing IP address, I can add sub domains, cnames, MX records etc, but they're all pointing at the same IP address.

    Then, if I have a webserver behind the firewall for example, any port 80 traffic arriving at the firewall/router is forwarded (internal NAT) to the (internal) IP address of the webserver (eg

    There's nothing wrong with IPcop, it will do all of this for you. I use monowall (, for me it's a lot better, (it's a live bootable disk so easy to try) but go with what you're comfortable with.
    \"One World, One Web, One Program.\" -- Advertisement for Internet Explorer.
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  6. #5
    Thanks everybody ... I made some changes and its working very nice now. I use ipcop because some friends use it and remmended it to me, and i think its a good firewall. The FBuilder is a good one too, ill take a look in it soon.. Sorry about my english people and thanks again.

  7. #6
    Linux Newbie
    Join Date
    Dec 2003
    it's better to try talk in English, even if you have a hard time to speak it
    Computers Are Like Air Conditioners... They\'re both useless with Windows open!

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