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Is it better (for efficiency) to use an IP address when setting a custom name server for my domain name rather than a domain like ns1.myserver.com?

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I can't figure out how this question could make sense. In what case do you have to choose between using a domain name or using an IP address? –  David Schwartz Mar 13 '12 at 2:28
    
This question is very vague; use IP address where? In general, using an IP address is best for daemons and servers in general. –  Mei Mar 13 '12 at 2:29
    
Apologies for the vagueness--my understanding of how this works is limited. I have a domain registered with a company other than where my web site is being hosted, and thus need to point the domain to my web host. –  devios Mar 13 '12 at 2:40

1 Answer 1

up vote 5 down vote accepted

When you specify a name server, you need to provide an NS record. NS records always point to a name. See Can the value for a NS record be an IP address?

$ host -t NS serverfault.com
serverfault.com name server ns3.serverfault.com.
serverfault.com name server ns4.serverfault.com.
serverfault.com name server ns1.serverfault.com.
serverfault.com name server ns2.serverfault.com.

Whatever hosts you list as your name servers must also resolve to an IP.

$ host ns3.serverfault.com
ns3.serverfault.com has address 69.59.196.217

Thus, if you're using an interface that is asking you to enter a name server's address, enter a DNS name.

Also, don't sweat the round-trip-time to find that A record -- the referring server also keeps the A record as "glue". That's why you usually also have to enter the IP address. When looking up the NS record, we get that additional data as well. With my registrar, I must first define a nameserver's name and IP combination before I can register the nameserver to the domain.

$ dig serverfault.com. @b.gtld-servers.net

; <<>> DiG 9.7.3-P3 <<>> serverfault.com. @b.gtld-servers.net.
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 30818
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 3, ADDITIONAL: 3
;; WARNING: recursion requested but not available

;; QUESTION SECTION:
;serverfault.com.           IN      A

;; AUTHORITY SECTION:
serverfault.com.    172800  IN      NS      ns1.serverfault.com.
serverfault.com.    172800  IN      NS      ns2.serverfault.com.
serverfault.com.    172800  IN      NS      ns3.serverfault.com.

;; ADDITIONAL SECTION:
ns1.serverfault.com.        172800  IN      A       64.34.119.33
ns2.serverfault.com.        172800  IN      A       64.34.119.34
ns3.serverfault.com.        172800  IN      A       69.59.196.217

;; Query time: 151 msec
;; SERVER: 192.33.14.30#53(192.33.14.30)
;; WHEN: Mon Mar 12 22:37:41 2012
;; MSG SIZE  rcvd: 135
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I could have sworn I've been able to add IP addresses into the name server settings for a domain before. Oddly enough my registrar has two apparent ways to set this: one under "name servers" and the other under NS record of DNS. How are these different? –  devios Mar 13 '12 at 2:37
    
@chaiguy Gave you some updates on glue records... it is very likely that you did have to add addresses when specifying name servers. –  Jeff Ferland Mar 13 '12 at 2:43
    
I think I get it, cheers :) –  devios Mar 13 '12 at 2:47

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