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question about dns and network

Discussion in 'Mac OS X Server, Xserve, and Networking' started by twoodcc, Jun 18, 2008.

  1. macrumors P6


    so, if you have dns running on a server, on your client you put in the ip address and domain name of the server in your networking preferences.

    now, lets say that my client is a laptop, connecting wirelessly to the network. and i put in that info and everything works.

    but then, the client leaves the network with his laptop, and goes home and connects to his home wireless network.

    how come the same info for dns stays there, even though he changed networks?
  2. macrumors regular

    It sounds like you put a static dns entry into your network preferences rather than using DHCP to populate these values?

    The surest way to verify what DNS server your client is using is to open terminal and type "dig www.google.com" This should return all of the DNS information but also at the bottom you'll see the server that was used for resolution.
  3. macrumors P6


    well, i think right now i have DHCP coming from the router, and not the server. could i put the server info into the router?
  4. macrumors member

    Where DHCP is running from makes no difference.

    DHCP leases the machine an IP address and tells the machine where to look for DNS servers. That information remains valid for a preset time (set on the DHCP server). 50% into that time, the client will try to renew its leased information.

    So, you laptop wanders onto your network and is leased an IP and DNS information. When it wanders off to a new network, if the machine has been restarted, it will still believe its on YOUR network. when you restarted the machine, it will release all IP information and look for a DHCP server during boot up.
  5. macrumors P6


    i'm still a little confused here. so the DNS info is served up from DHCP? so, DNS is coming from my server, and DHCP is coming from the router. so do i tell the router to send out the server's DNS info?
  6. JNB
    macrumors 604


    At the client side:
    DHCP, no DNS entry - will ask for an IP address and the DNS server to be used, populated automatically from the router
    DCHP, manual DNS entry - will ask for an IP address and will attempt to pass network requests through the DNS server specified, but "should" find other DNS servers on the network you're attached to.

    The router acts as the DNS Server for devices downstream from it and provides the domains to be searched. You can specify additional domains, but the order they appear sometimes can cause a lot of delays while it's attempting to get routing information from the first one on the list and takes a while to time out and move to the next one.

    Attached Files:

  7. macrumors P6



    thank you, this is exactly what i'm talking about.

    now how can i get my dns info to be populated automatically like yours?

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