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I am slightly confused between DNS and Name server. Are they the same thing or is there a difference between two?

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4 Answers

up vote 25 down vote accepted

There is no such thing as a Domain Name Server.

DNS stands for Domain Name System, which is simply a hierarchy of Name Servers that has the intent to translate host names into IP addresses on a global scale. A name server hosts or caches these translations, in the case where they are hosted the name server is often called a DNS Server.

Counting all name servers is a bit tricky, because you can't simply enumerate all the domains.

Let me give you an example on resolving superuser.com in a non-cached way:

  • The name server that I use is 192.168.1.1.

    This is my local router which caches DNS entries, it has a Hosts file to reroute malicious domains.

  • The router has the name servers 8.8.6.6 and 8.8.8.8 set, known as Google DNS, they also cache.

  • Google DNS will contact authoritative root name servers, which are the top of the DNS hierarchy.

  • Google DNS will contact the .com name servers, the IP of which it received from the ARNs.

  • Google DNS will contact the DNS server for superuser.com, of which IP it received from .com.

    A simply whois reveals:

    NS1.SERVERFAULT.COM
NS2.SERVERFAULT.COM
NS3.SERVERFAULT.COM

    The IPs for these name servers are known as they are registered at the .com name server, when you register a new domain you always have to fill in the DNS servers that you use along their IP.

  • Google DNS will contact the DNS servers of superuser.com to find the IP of superuser.com:

    nslookup superuser.com NS1.SERVERFAULT.COM
Server:  NS1.SERVERFAULT.COM
Address:  64.34.119.33

Name:    superuser.com
Address:  64.34.119.12

I would suggest you to read through Domain Name System and Name Servers for more details.

The term name servers are also used in different contexts, read Spiff's answer for more.

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4  
Side fact: . is the root domain, example: google.com. Note the extra dot in the URL. :) – Tom Wijsman Aug 7 '11 at 9:54
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+1 great post, thanks – MaxMackie Aug 7 '11 at 21:00
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@Tom: Thanks for that great explanation. I am pretty new to the networking side of IT. But I thought, some where a record must be maintained about the count of TLD and the list of nameservers and the webaddress registered under them. – Kunal Aug 8 '11 at 1:30
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@Kunal: Maybe, I'm just unaware of it and it seems hard to find so I think such count does not exist... – Tom Wijsman Aug 8 '11 at 12:14
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+1 great post. Ta! – Andrew Sep 27 '12 at 15:35
up vote 8 down vote

Tricky!

A DNS Server typically is for converting FQDN (www.xxx.com) to IP Addresses (192.168.0.1).

(A DNS Server also does a lot more, it can perform reverse lookups, and in recent years does a lot of other tasks with text tags, geo-ip and a lot more).

On the other hand, a Name Server typically is a DNS Server, however, the name "Name Server" is typically used to locate a DNS Server.

For example, On a Whois record, a Name Server is typically the address for the DNS server that hosts the records for that domain.

As for how many are there - how long is a piece of string! This is an impossible question to answer... As a guess, I would put it in to the hundreds of thousands, if not low millions (for publicly accessible DNS Servers).

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There are 13 names for the root nameservers, but they exist in more than 13 physical locations. – soandos Aug 7 '11 at 8:36
up vote 6 down vote

In some contexts, the term "name server" can refer to servers that aren't part of the Internet Domain Name System. For example, a WINS server is a name server for Microsoft's legacy proprietary networking protocols. There may have been other legacy LAN systems that had their own types of name servers that weren't part of Internet DNS.

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+1 for extra information, haven't considered this. – Tom Wijsman Aug 7 '11 at 20:53
+1 for mentioning what I immediately thought of when I read the question. Unfortunately, then -1 again for gross abuse of the word "legacy". – JdeBP Aug 8 '11 at 0:24
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@JdeBP I think you misread me. My use of "legacy" has no value judgment, so it's not a pejorative. I mean it simply in the sense of legacy systems: Something left over but still in use from a previous generation of technology. English is an ever-changing language and this usage of "legacy" has been in common use in the IT industry for several decades now. I agree with your page that it's sometimes misused as a pejorative, but there are also valid uses of it in IT discussions. – Spiff Aug 8 '11 at 0:48
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@JdeBP I recall IT magazines in the very early 90's, as the burgeoning of PC LANs had ushered in the "client-server" era, referring to minicomputers and mainframes as "legacy systems". I'll bet I can find citations from the early 80's as well. – Spiff Aug 8 '11 at 1:08
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In the context above, the word "legacy" was clearly not used as a pejorative. It's clear the tone was informative and not opinionated. – surfasb Aug 8 '11 at 1:23
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up vote 3 down vote

The acronym DNS means Domain Name System. It is a distributed system for translating host names (and other data) to IP addresses in a large scale (world). The name server is usually what people call the local DNS server that a workstation/PC can use as its entry point into the DNS. It will resolve local names, but delegates to other names servers for those it can't answer.

There are many name servers, but you don't need to know how many since they are queried as needed. There are only a few "root" name servers (the DNS is hierarchical).

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