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DHCP and manual config of DNS

Discussion in 'Windows Server 2003 / 2008 / 2012 Exams' started by flex22, Jan 23, 2004.

  1. flex22

    flex22 Gigabyte Poster

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    I just read that DHCP has to provide the DNS servers.At first I thought to myself, well, why does it have to.I mean it can give IP addresses out, and that's it.
    But I suppose that the whole point of DHCP is to make life easy for clients, therefore as well as giving them an IP address, they sort them out with a DNS while theyre at it.

    Thing that got me though is this.I read in my book that you can't a configure client manually with an IP address when the client is set up using DHCP.

    But what if you wanted that particular client, and that client alone, to use another DNS server.
    Would this mean that you'd have to change it's IP address also :?:

    My thinking is that you'd remove one of your allocated IP addresses from the DHCP scope, and then go to your client configure it manually with the IP.Is this right :?:
    Thereafter you could specify a DNS manually.

    Sorry just my enquiring mind.So hard to take things in when I keep thinking of every imaginable scenario.

    Thanks :!:
     
  2. Phil
    Honorary Member

    Phil Gigabyte Poster

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    You could do that flex or you could configure a user class option and assign it to the clients you want different options for, I dug up some links

    Understanding user and vendor classes

    To create a new user or vendor class

    Assigning options to a user class

    Assigning User Class to a client
     
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  3. dreec

    dreec Nibble Poster

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    Flex - Just to confirm.

    If a client is set up to obtain an IP address automatically then it gets the IP address from a DHCP Server.
    This means you cannot configure that client with a static IP address.

    However even if the client gets its IP address from a DHCP server, you still have the option to configure the DNS Server address manually (statically).

    **This does not work the other way round. If client is configured with a static IP address the DNS server IP address must also be configured static.**

    The manually specified DNS server IP address will NOT be overwritten by the DHCP specified DNS Server IP address. (this is because you have configured the client to a static DNS IP address and therefore will ignore the 006 DNS option in the DHCPACK message.)

    If you wanted multiple clients to use a different DNS server then the easy way would be to create 2 different scopes on the DHCP Server then set the 006 DNS Server option at the scope level rather than at the global (server) level.

    If you wanted multiple clients to use a different DNS server, and these clients are on the same subnet as other clients which you DO NOT want to use the different DNS server, then a user class option would be the best choice.

    Quick Recap;

    One Client requires different DNS config. - Manually config

    Multiple clients, different subnets - 006 at scope level on DHCP

    Multiple clients, same subnet - 006 on user class on DHCP

    Hope this helps
     
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  4. flex22

    flex22 Gigabyte Poster

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    I was a bit lazy here to be honest.I just took it that I couldn't set the DNS IP differently than the client IP.I couldn't be bothered going to the TCP/IP properties and looking.Completely idle of me. :soz

    Thanks :!:
     
  5. Phil
    Honorary Member

    Phil Gigabyte Poster

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    well answered dreec, I got so sidetracked with the user classes I forgot you could manualy assign the DNS settings :oops:
     
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    WIP: 2003 Upgrade, CCNA Upgrade

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