Domain Name Basics
DNS, Domains and ICANN
a short introduction for newcomers
Domain Name System (DNS)
DNS is a hierarchical distributed naming system to translate domain names to IP
addresses, which makes websites easier to remember, such as
united-domains.de instead of 220.127.116.11
The domain name space is a tree and its root is a „dot“.
uk com de
2 | Tobias Sattler, CIO www.united-domains.de
Root Name Server
To resolve domain names root name servers are needed.
The root server zone file contains all top-level domains (.de, .com, .net) and the
according IP addresses of their authoritative name server.
There are 13 root name servers and they are available via IPv4 and IPv6.
These servers are load balanced across multiple computing resources; therefore
there are actually more than hundreds of servers world wide, minimizing response
time and server overload.
Source: https://commons.wikimedia.org/wiki/File:Root-current.svg - Effective 03/2016
3 | Tobias Sattler, CIO www.united-domains.de
What is a domain name?
It is an unique string within the domain name system (DNS).
The point at the end of a domain name will be ignored by most programs, like
browsers and email clients, but it is actually there.
Subdomain Domain Top-Level Root
www. united-domains. de .
4 | Tobias Sattler, CIO www.united-domains.de
What is a top-level domain?
It is the name of the top tier and it is divided in two groups:
Generic TLDs (gTLDs) like .com, .net and .org
Country Code TLDs (ccTLDs) like .de, .io, .uk and many more.
Actually there are more than 1,000 gTLDs, e.g.:
.aero, .asia, .berlin, .bike, .biz, .cat, .club, .com, .coop, .edu, .gov, .guru, .info, .int, .jobs, .mil, .mobi,
.museum, .name, .net, .ngo, .nyc, .org, .post, .pro, .tel, .travel, .xyz, .xxx
There are over 200 ccTLDs, e.g.:
.au, .br, .ca, .cn, .co, .de, .eu, .fr, .hk, .it, .io, .me, .nl, .ru, .tk, .uk, .us, .za
5 | Tobias Sattler, CIO www.united-domains.de
Who is maintaining the DNS?
The DNS is maintained by the Internet Assigned Numbers Authority (IANA) and the
Internet Corporation for Assigned Names and Numbers (ICANN).
TLDs are maintained by Registries.
Domain names are usually maintained by Registrars, such as GoDaddy, 1&1
Internet, united-domains, etc.
6 | Tobias Sattler, CIO www.united-domains.de
Who are IANA and ICANN?
Internet Assigned Numbers Authority (IANA) is a department of Internet
Corporation for Assigned Names and Numbers (ICANN).
IANA is broadly responsible for the allocation of globally unique names and
numbers used in Internet protocols that are published as Request for Comments
ICANN oversees global IP address allocation, autonomous system number
allocation, root zone management in the Domain Name System (DNS), media types,
and other Internet Protocol-related symbols and numbers.
ICANN is a nonprofit private organization and was incorporated 1998
ICANN's primary principles of operation have been described as helping preserve
the operational stability of the Internet.
7 | Tobias Sattler, CIO www.united-domains.de
What is ICANN exactly doing?
ICANN‘s primary role is to coordinate the allocation of IP addresses and TLDs.
ICANN is developing policies for gTLD domain names and revises these policies
from time to time.
Policies’ development and reviews are always done within working groups. These
working groups are composed of staff from any affected and/or interested party.
Policies have to go through public comment. Everyone is allowed to comment.
8 | Tobias Sattler, CIO www.united-domains.de
How is ICANN organized?
ICANN has multiple bodies and their duties are defined in the bylaws.
This list is not exhaustive, but the important bodies besides the Board of Directors
are the Address Supporting Organization (ASO), Country Code Names Supporting
Organization (ccNSO), Generic Names Supporting Organization (GNSO), Advisory
Committees (AC) and Nominating Committee.
gTLD Registries and Registrars are part of the GNSO and have direct contracts with
9 | Tobias Sattler, CIO www.united-domains.de
Address Support Organization
Represents the Regional Internet Registries (RIRs), which are responsible for
allocation of IP address blocks.
IP addresses are necessary for all Internet communications.
There are 5 RIRs:
Réseaux IP Européens Network Coordination Centre (RIPE NCC)
American Registry for Internet Numbers (ARIN)
Asia-Pacific Network Information Centre (APNIC)
Latin American and Caribbean Internet Addresses Registry (LACNIC)
African Network Information Centre (AfriNIC)
Source: https://commons.wikimedia.org/wiki/File:Regional_Internet_Registries_world_map.svg - Effective 03/2016
10 | Tobias Sattler, CIO www.united-domains.de
Country Code Names Supporting Organization
The Country Code Names Supporting Organization (ccNSO) is a body within the
ICANN structure created for and by ccTLD managers.
It has about 150 members representing the country code top level domains
(ccTLDs), such as Nominet (.uk), DENIC (.de), SGNIC (.sg), etc.
Supplying and providing a platform for technical cooperation and a forum for ccTLD
related problems and issues.
Advising the ICANN Board on global policies related to ccTLD issues.
Policy development through the ccNSO Council.
11 | Tobias Sattler, CIO www.united-domains.de
Generic Names Supporting Organization
Develops policies and recommendations for all gTLDs.
The GNSO consists of 4 stakeholder groups:
Commercial Stakeholder Group (CSG)
Non-Commercial Stakeholder Group (NCSG)
Registry Stakeholder Group (RySG)
Registrar Stakeholder Group (RrSG)
Source: http://gnso.icann.org/en/about/gnso-council.htm - Effective 03/2016
12 | Tobias Sattler, CIO www.united-domains.de
There are 4 essential committees:
Governmental Advisory Committee (GAC)
At-Large Advisory Committee (ALAC)
Security and Stability Advisory Committee (SSAC)
Root Server System Advisory Committee (RSSAC)
GAC membership consists of national governments and, usually in an observer
capacity, multinational governmental and treaty organizations and public
authorities (including all the UN agencies with a direct interest in global Internet
governance such as the ITU, UNESCO and WIPO). There are more than 160
members organized within the GAC.
ALAC is the primary organizational home within ICANN for individual Internet users.
There are over 190 members, such as Wikimedia and ISOC.
SSAC and RSSAC are providing recommendations about security and technical risks.
13 | Tobias Sattler, CIO www.united-domains.de
Please get in touch if you have any further questions:
14 | Tobias Sattler, CIO www.united-domains.de