List of all the domain name extensions in the world (Ohhh well, almost all I should say, I am sure I have missed one or two out especially those funny domain extensions you need a plug in to see).

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Generic Top Level Domain Names (gTLD)
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.aero
.biz
.com
.coop
.info
.museum
.name
.net
.org
.pro
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Second Level Domain Names (sLD)
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.ac Ascension Island
.ad Andorra
.ae United Arab Emirates
.af Afghanistan
.ag Antigua and Barbuda
.ai Anguilla
.al Albania
.am Armenia
.an Netherlands Antilles
.ao Angola
.aq Antarctica
.ar Argentina
.as American Samoa
.at Austria
.au Australia
.aw Aruba
.az Azerbaijan
.ba Bosnia and Herzegovina
.bb Barbados
.bd Bangladesh
.be Belgium
.bf Burkina Faso
.bg Bulgaria
.bh Bahrain
.bi Burundi
.bj Benin
.bm Bermuda
.bn Brunei Darussalam
.bo Bolivia
.br Brazil
.bs Bahamas
.bt Bhutan
.bv Bouvet Island
.bw Botswana
.by Belarus
.bz Belize
.ca Canada
.cc Cocos (Keeling) Islands
.cd Congo
.cf Central African Republic
.cg Congo
.ch Switzerland
.ci Cote d'Ivoire
.ck Cook Islands
.cl Chile
.cm Cameroon
.cn China
.co Colombia
.cr Costa Rica
.cu Cuba
.cv Cap Verde
.cx Christmas Island
.cy Cyprus
.cz Czech Republic
.de Germany
.dj Djibouti
.dk Denmark
.dm Dominica
.do Dominican Republic
.dz Algeria
.ec Ecuador
.ee Estonia
.eg Egypt
.eh Western Sahara
.er Eritrea
.es Spain
.et Ethiopia
.fi Finland
.fj Fiji
.fk Falkland Islands (Malvina)
.fm Federal State of Micronesia
.fo Faroe Islands
.fr France
.ga Gabon
.gd Grenada
.ge Georgia
.gf French Guiana
.gg Guernsey
.gh Ghana
.gi Gibraltar
.gl Greenland
.gm Gambia
.gn Guinea
.gp Guadeloupe
.gq Equatorial Guinea
.gr Greece
.gs South Georgia and the South Sandwich Islands
.gt Guatemala
.gu Guam
.gw Guinea-Bissau
.gy Guyana
.hk Hong Kong
.hm Heard and McDonald Islands
.hn Honduras
.hr Croatia/Hrvatska
.ht Haiti
.hu Hungary
.id Indonesia
.ie Ireland
.il Israel
.im Isle of Man
.in India
.io British Indian Ocean Territory
.iq Iraq
.ir Iran (Islamic Republic of)
.is Iceland
.it Italy
.je Jersey
.jm Jamaica
.jo Jordan
.jp Japan
.ke Kenya
.kg Kyrgyzstan
.kh Cambodia
.ki Kiribati
.km Comoros
.kn Saint Kitts and Nevis
.kp Democratic People's Republic Korea
.kr Republic of Korea
.kw Kuwait
.ky Cayman Islands
.kz Kazakhstan
.la Lao People's Democratic Republic
.lb Lebanon
.lc Saint Lucia
.li Liechtenstein
.lk Sri Lanka
.lr Liberia
.ls Lesotho
.lt Lithuania
.lu Luxembourg
.lv Latvia
.ly Libyan Arab Jamahiriya
.ma Morocco
.mc Monaco
.md Republic of Moldova
.mg Madagascar
.mh Marshall Islands
.mk Former Yugoslav Republic Macedonia
.ml Mali
.mm Myanmar
.mn Mongolia
.mo Macau
.mp Northern Mariana Islands
.mq Martinique
.mr Mauritania
.ms Montserrat
.mt Malta
.mu Mauritius
.mv Maldives
.mw Malawi
.mx Mexico
.my Malaysia
.mz Mozambique
.na Namibia
.nc New Caledonia
.ne Niger
.nf Norfolk Island
.ng Nigeria
.ni Nicaragua
.nl Netherlands
.no Norway
.np Nepal
.nr Nauru
.nu Niue
.nz New Zealand
.om Oman
.pa Panama
.pe Peru
.pf French Polynesia
.pg Papua New Guinea
.ph Philippines
.pk Pakistan
.pl Poland
.pm St. Pierre and Miquelon
.pn Pitcairn Island
.pr Puerto Rico
.ps Palestinian Territories
.pt Portugal
.pw Palau
.py Paraguay
.qa Qatar
.re Reunion Island
.ro Romania
.ru Russian Federation
.rw Rwanda
.sa Saudi Arabia
.sb Solomon Islands
.sc Seychelles
.sd Sudan
.se Sweden
.sg Singapore
.sh St. Helena
.si Slovenia
.sj Svalbard and Jan Mayen Islands
.sk Slovak Republic
.sl Sierra Leone
.sm San Marino
.sn Senegal
.so Somalia
.sr Suriname
.st Sao Tome and Principe
.sv El Salvador
.sy Syrian Arab Republic
.sz Swaziland
.tc Turks and Caicos Islands
.td Chad
.tf French Southern Territories
.tg Togo
.th Thailand
.tj Tajikistan
.tk Tokelau
.tm Turkmenistan
.tn Tunisia
.to Tonga
.tp East Timor
.tr Turkey
.tt Trinidad and Tobago
.tv Tuvalu
.tw Taiwan
.tz Tanzania
.ua Ukraine
.ug Uganda
.uk United Kingdom
.um US Minor Outlying Islands
.us United States
.uy Uruguay
.uz Uzbekistan
.va Holy See (City Vatican State)
.vc Saint Vincent and the Grenadines
.ve Venezuela
.vg Virgin Islands (British)
.vi Virgin Islands (USA)
.vn Vietnam
.vu Vanuatu
.wf Wallis and Futuna Islands
.ws Western Samoa
.ye Yemen
.yt Mayotte
.yu Yugoslavia
.za South Africa
.zm Zambia
.zw Zimbabwe