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  1. #1
    Join Date
    Sep 2004
    Location
    Beaverton, OR
    Posts
    261

    Can a nameserver be specified in an A record by another nameserver?

    Here's the jist:

    1) I use DNSMadeEasy for a couple of my important domains so I can utilize their failover service.
    2) I use my own nameservers for everyone else.

    At my register (GoDaddy) I've added host entries to my domain (let's call it host.com) for ALL of my nameservers: DNSMadeEasy and mine. For example here are my host entries:

    1) nsdme0.host.com = 55.55.55.55 (DNSMadeEasy)
    2) nsdme1.host.com = 56.55.55.55 (DNSMadeEasy)
    3) nsdme2.host.com = 57.55.55.55 (DNSMadeEasy)
    4) nsdme3.host.com = 58.55.55.55 (DNSMadeEasy)
    5) nsdme4.host.com = 59.55.55.55 (DNSMadeEasy)
    6) ns1.host.com = 60.55.55.55 (mine)
    7) ns2.host.com = 61.55.55.55 (mine)

    At the register I've then configured host.com to use the first five nameservers for itself, the DNSMadeEasy nameservers.

    For less critical sites that I host I simply point them to ns1.host.com and ns2.host.com, my nameservers.

    Now, here's the twist. If I use dig to look up www.host.com I get:

    Code:
    [[email protected] ~]# dig +trace www.host.com
    
    ; <<>> DiG 9.3.3rc2 <<>> +trace www.host.com
    ;; global options:  printcmd
    .                       220048  IN      NS      D.ROOT-SERVERS.NET.
    			...........................................
    .                       220048  IN      NS      K.ROOT-SERVERS.NET.
    ;; Received 228 bytes from 66.63.160.2#53(66.63.160.2) in 1 ms
    
    net.                    172800  IN      NS      J.GTLD-SERVERS.net.
    			...........................................
    net.                    172800  IN      NS      G.GTLD-SERVERS.net.
    ;; Received 497 bytes from 128.8.10.90#53(D.ROOT-SERVERS.NET) in 74 ms
    
    host.com.     172800  IN      NS      nsdme0.host.com.
    host.com.     172800  IN      NS      nsdme1.host.com.
    host.com.     172800  IN      NS      nsdme2.host.com.
    host.com.     172800  IN      NS      nsdme3.host.com.
    host.com.     172800  IN      NS      nsdme4.host.com.
    ;; Received 225 bytes from 192.48.79.30#53(J.GTLD-SERVERS.net) in 125 ms
    
    www.host.com. 1800    IN      CNAME   host.com.
    host.com.     75      IN      A       60.55.55.55
    host.com.     86400   IN      NS      nsdme2.host.com.
    host.com.     86400   IN      NS      nsdme1.host.com.
    host.com.     86400   IN      NS      nsdme5.host.com.
    host.com.     86400   IN      NS      nsdme0.host.com.
    host.com.     86400   IN      NS      nsdme4.host.com.
    host.com.     86400   IN      NS      nsdme3.host.com.
    ;; Received 276 bytes from 123.123.123.123#53(nsdme0.host.com) in 68 ms
    BUT, if I lookup the nameserver (ns1.host.com) I get:

    Code:
    [[email protected] ~]# dig +trace ns1.host.com
    
    ; <<>> DiG 9.3.3rc2 <<>> +trace ns1.host.com
    ;; global options:  printcmd
    .                       218964  IN      NS      M.ROOT-SERVERS.NET.
    			...........................................
    .                       218964  IN      NS      K.ROOT-SERVERS.NET.
    ;; Received 228 bytes from 66.63.160.2#53(66.63.160.2) in 1 ms
    
    net.                    172800  IN      NS      H.GTLD-SERVERS.net.
    			...........................................
    net.                    172800  IN      NS      G.GTLD-SERVERS.net.
    ;; Received 497 bytes from 202.12.27.33#53(M.ROOT-SERVERS.NET) in 115 ms
    
    ns1.host.com. 172800  IN      A       60.55.55.55
    host.com.     172800  IN      NS      nsdme0.host.com.
    host.com.     172800  IN      NS      nsdme1.host.com.
    host.com.     172800  IN      NS      nsdme2.host.com.
    host.com.     172800  IN      NS      nsdme3.host.com.
    host.com.     172800  IN      NS      nsdme4.host.com.
    ;; Received 241 bytes from 192.54.112.30#53(H.GTLD-SERVERS.net) in 151 ms
    What I've realized is that the actual IP addresses for nameserver host entries come from a higher level server than my own, in this case H.GTLD-SERVERS.net. I guess this makes sense but I just hadn't realized it before. It looks like I don't even need to have record entries in my DNS records for the host nameservers.

    Now for the question. Can I:

    1) Remove my custom host nameserver entries from my register.
    2) Add entries in my DNSMadeEasy records to specify the location of ns1.host.com and ns2.host.com.
    3) Use the failover provided by DNSMadeEasy to also fail-over my DNS entries for my nameservers?

    I know this would require one more hop if it works but it would allow me to provide failover ability to fifty domains without having to purchase the extra domains at DNSMadeEasy.

    Thoughts?
    Matkin
    Last edited by RelativeDesign-Jerret; 04-04-2008 at 02:06 PM. Reason: fixed typo

  2. #2
    Join Date
    Oct 2007
    Posts
    446
    You would not be able to "just" set your NS record A records in DNS Made Easy. You will need to register them with the respective registry. This is done through your registrar.

    Many regsitrars will not even allow you to use a name server that is not set at the TLD level.

  3. #3
    Join Date
    Feb 2005
    Location
    Australia
    Posts
    5,842
    To add a bit more detail, you're talking about "glue" - IP addresses supplied by the parent nameservers along with the names of your nameservers. It's this you're setting when you register a nameserver at your registrar. In some cases (notably for client domains in other tlds) and for some visitors what you're proposing might work but for consistent, reliable results you really need both glue and A records.

    So in answer to your questions:
    1. No.
    2. Yes - you should do this anyway (but they can't failover).
    3. Not unless you use DNSme's nameservers and pay for them.
    Chris

    "Some problems are so complex that you have to be highly intelligent and well informed just to be undecided about them." - Laurence J. Peter

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