Anatomy of a domain name

In this section, we'll break out the functional components of a "domain name" from the perspective of the overall ecosystem on the left side of the diagram in Figure 1.1.

The "domain name" in this context is a naming entity such as example.com or any other domain we register via a domain registrar.

Registration details for domain names are kept in publicly accessible databases called WHOIS servers. The record for a given domain name is typically called a WHOIS record.

We'll look at a WHOIS record for a domain name and break out the logical components of the registration details. Each section has a distinct meaning and function within the overall ecosystem.

If you run the following example whois command on your own system, you may see a different output depending on what kind of WHOIS client you are using. For our examples, we are just using a command line whois command, which you typically find on most Linux or Unix systems.

A note on examples and example.com.

example.com is an example of a domain name. It (and several others) are specifically reserved by IANA to serve the purpose of providing examples without requiring prior permission from anybody. RFC 2606 describes "Reserved Top-Level DNS Names" and their functions. Throughout the book, I use example.com wherever possible. In cases where I need to show some specific element not present within example.com , I'll use different domain names as required. I sometimes employ the nonexistent top-level domain (TLD) .dom in examples (even though the reserved TLD .example exists and has been reserved for this purpose, it is, like so many of these "new TLDs," long and cumbersome).

WHOIS output for https://www.packtpub.com/—the publisher of this book is shows as follows:

$ whois packtpub.com
Domain Name: PACKTPUB.COM
Domain ID: 97706392_DOMAIN_COM-VRSN
Registrar WHOIS Server: whois.easydns.com
Registrar URL: http://www.easydns.com
Updated Date: 2015-09-15T21:46:16Z
Creation Date: 2003-05-09T14:34:02Z
Registrar Registration Expiration Date: 2024-05-09T14:34:02Z
Registrar: easyDNS Technologies, Inc.
Registrar IANA ID: 469
Domain Status: clientTransferProhibited https://icann.org/epp#clientTransferProhibited
Domain Status: clientUpdateProhibited https://icann.org/epp#clientUpdateProhibited
Registry Registrant ID:
Registrant Name: Domain Manager
Registrant Organization: Packt Publishing
Registrant Street: 2nd Floor Livery Place, 35 Livery Street
Registrant City: Birmingham
Registrant State/Province: West Midlands
Registrant Postal Code: B3 2PB
Registrant Country: GB
Registrant Phone: +44.1212656484
Registrant Phone Ext:
Registrant Fax:
Registrant Email: packtsupport@packtpub.com
Registry Admin ID:
Admin Name: Domain Manager
Admin Organization: Packt Publishing
Admin Street: 2nd Floor Livery Place, 35 Livery Street
Admin City: Birmingham
Admin State/Province: West Midlands
Admin Postal Code: B3 2PB
Admin Country: GB
Admin Phone: +44.1212656484
Admin Phone Ext:
Admin Fax:
Admin Fax Ext:
Admin Email: packtsupport@packtpub.com
Registry Tech ID:
Tech Name: Domain Manager
Tech Organization: Packt Publishing
Tech Street: 2nd Floor Livery Place, 35 Livery Street
Tech City: Birmingham
Tech State/Province: West Midlands
Tech Postal Code: B3 2PB
Tech Country: GB
Tech Phone: +44.1212656484
Tech Fax:
Tech Fax Ext:
Tech Email: packtsupport@packtpub.com
Name Server: DNS3.EASYDNS.ORG
Name Server: DNS1.EASYDNS.COM
Name Server: DNS2.EASYDNS.NET
Name Server: DNS4.EASYDNS.INFO
DNSSEC: unsigned
Registrar Abuse Contact Email: abuse@easydns.com
Registrar Abuse Contact Phone: +1.4165358672

WHOIS record formats differ between TLDs—and we'll discuss some of the key differences in these when we take a closer look at WHOIS—but they all share similar characteristics that can help us dissect the various "moving parts" of a domain; they are the following:

• Registry details
• Domain registrant
• Administrative contact
• Technical contact
• Domain status
• DNS details