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Dns master/slave confusion..

Discussion in 'General Server' started by mikewaals, Jan 16, 2013.

  1. mikewaals

    mikewaals Guest

    Hi Fellas,
    I am new to linux and now i am studying about Dns and some how i got understading about it..and i know setting up chacing name server..but in setting master/slave server in our local server..i have big big confusion...

    i know what is master and slave...so what is purpose of setting our own master and slave dns server..why not just point out to dns server like open dns ..etc..

    and i saw some tutrorial where they put domain name and namse server (ns1.blabla.com) in named.conf..where to obtain this ns1.bla bla.com

    i have big confusion..so kindly help me to clear my confusion..

    Thanks in advance
  2. hackinjack

    hackinjack Guest

    I am not sure I understand the question - but I'll try to help. You don't have to host a master or slave DNS server
    on your own machine/s - and it's a very, very bad idea to run both a master and slave on the same physical machine - master and slave should ideally not even be in the same data centre for any kind of production system.

    I suspect you may be getting the DNS resolver configuration confused with DNS server configuration. On a linux system the nameserver configuration will be found in the file /etc/resolv.conf - which frequently just has a couple of lines in with the following information:

    in this example the nameservers are those of google, but equally they could point to opendns or wherever you want. This is not a DNS SERVER configuration for master or slave though - this is just a DNS resolver configuration.

    Does that help?
  3. mikewaals

    mikewaals Guest

    Thanks brother for your reply. But yes u did not understand my question maybe its my poor english. So sorry for that. But Finally my confusion clear.and Now i know that master /slave is a zone database for particular company domain. and in that zone db file , we point out web,ftp,mail server ip. and salve update zone database from master after particular time or according to serial number given in master. If master is down then slave is used for load balancing..Am i right? please correct me if i am wrong.
  4. hackinjack

    hackinjack Guest

    You're almost there, but careful with your terminology -

    Load Balancing != Resilience

    If the master is down, unless you have a load balancer device/server in your network, DNS requests TO that server will time out.

    Usually this means the lookup request is re-tried using the secondary server in the CLIENT DNS config. It can lead to slow performance as a browser will wait until the initial DNS lookup fails before timing out and trying the secondary DNS server.

    However you correctly figured out that you can set up DNS servers to slave off a master. Fresh copies of the zone files will be copied if the serial number is lower.

    The services you mention above, web, ftp, mail etc. are indeed defined in the master zone file. DNS slaves just make copies of the master, that does not address load balancing.

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