CT320: Network and System Administration

Fall 2019

Top Level Domains

Show Lecture.TopLevelDomains as a slide show.

CT320 Top Level Domains

Top Level Domains Trivia

https://data.iana.org/TLD/tlds-alpha-by-domain.txt

The Original Top-Level Domains

About 1984, the original TLDs were created:

Country Codes

There are 248 two-letter ASCII country codes, as assigned in ISO 3166-1:

.ac .ad .ae .af .ag .ai .al .am .ao .aq .ar .as .at .au .aw .ax .az .ba .bb .bd .be .bf .bg .bh .bi .bj .bm .bn .bo .br .bs .bt .bv .bw .by .bz .ca .cc .cd .cf .cg .ch .ci .ck .cl .cm .cn .co .cr .cu .cv .cw .cx .cy .cz .de .dj .dk .dm .do .dz .ec .ee .eg .er .es .et .eu .fi .fj .fk .fm .fo .fr .ga .gb .gd .ge .gf .gg .gh .gi .gl .gm .gn .gp .gq .gr .gs .gt .gu .gw .gy .hk .hm .hn .hr .ht .hu .id .ie .il .im .in .io .iq .ir .is .it .je .jm .jo .jp .ke .kg .kh .ki .km .kn .kp .kr .kw .ky .kz .la .lb .lc .li .lk .lr .ls .lt .lu .lv .ly .ma .mc .md .me .mg .mh .mk .ml .mm .mn .mo .mp .mq .mr .ms .mt .mu .mv .mw .mx .my .mz .na .nc .ne .nf .ng .ni .nl .no .np .nr .nu .nz .om .pa .pe .pf .pg .ph .pk .pl .pm .pn .pr .ps .pt .pw .py .qa .re .ro .rs .ru .rw .sa .sb .sc .sd .se .sg .sh .si .sj .sk .sl .sm .sn .so .sr .ss .st .su .sv .sx .sy .sz .tc .td .tf .tg .th .tj .tk .tl .tm .tn .to .tr .tt .tv .tw .tz .ua .ug .uk .us .uy .uz .va .vc .ve .vg .vi .vn .vu .wf .ws .ye .yt .za .zm .zw

Non-country geographic domains

In addition to the two-letter country code domains, there are a growing number of geographic domains, including:

https://wikipedia.org/wiki/List_of_Internet_top-level_domains#Geographic_top-level_domains

.US

Unfortunately, .us is a disaster, due to the overly-complex naming scheme enforced until 2002:

That’s one .gov, one .org, and one .com. Uniformity!

Map

Second Wave

In the early 2000s, several TLDs were added:

Speculation

As of October 2017, applin.com was available for $3,495 00.

Non-International Domains

We are in a speculation bubble, as top-level domains are being sold for $$$. Current top-level domains:

.aaa .aarp .abb .abbott .abbvie .abc .able .abogado .abudhabi .ac .academy .accenture .accountant .accountants .aco .actor .ad .ads .adult .ae .aeg .aero .aetna .af .afl .africa .ag .agakhan .agency .ai .aig .airbus .airforce .airtel .akdn .al .alibaba .alipay .allfinanz .allstate .ally .alsace .alstom .am .amazon .americanexpress .americanfamily .amex .amfam .amica .amsterdam .analytics .android .anquan .anz .ao .aol .apartments .app .apple .aq .aquarelle .ar .arab .aramco .archi .army .arpa .art .arte .as .asda .asia .associates .at .athleta .attorney .au .auction .audi .audible .audio .auspost .author .auto .autos .aw .aws .ax .axa .az .azure .ba .baby .baidu .banamex .band .bank .bar .barcelona .barclaycard .barclays .barefoot .bargains .baseball .basketball .bauhaus .bayern .bb .bbc .bbt .bbva .bcg .bcn .bd .be .beats .beauty .beer .bentley .berlin .best .bestbuy .bet .bf .bg .bh .bharti .bi .bible .bid .bike .bing .bingo .bio .biz .bj .black .blackfriday .blockbuster .blog .bloomberg .blue .bm .bms .bmw .bn .bnpparibas .bo .boats .boehringer .bofa .bom .bond .boo .book .booking .bosch .bostik .boston .bot .boutique .box .br .bradesco .bridgestone .broadway .broker .brother .brussels .bs .bt .build .builders .business .buy .buzz .bv .bw .by .bz .bzh .ca .cab .cafe .cal .call .calvinklein .cam .camera .camp .canon .capetown .capital .capitalone .car .caravan .cards .care .career .careers .cars .casa .case .cash .casino .cat .catering .catholic .cba .cbn .cbre .cc .cd .center .ceo .cern .cf .cfa .cfd .cg .ch .chanel .channel .charity .chase .chat .cheap .chintai .christmas .chrome .church .ci .cipriani .circle .cisco .citadel .citi .citic .city .ck .cl .claims .cleaning .click .clinic .clinique .clothing .cloud .club .clubmed .cm .cn .co .coach .codes .coffee .college .cologne .com .commbank .community .company .compare .computer .comsec .condos .construction .consulting .contact .contractors .cooking .cool .coop .corsica .country .coupon .coupons .courses .cpa .cr .credit .creditcard .creditunion .cricket .crown .crs .cruise .cruises .cu .cuisinella .cv .cw .cx .cy .cymru .cyou .cz .dabur .dad .dance .data .date .dating .datsun .day .dclk .dds .de .deal .dealer .deals .degree .delivery .dell .deloitte .delta .democrat .dental .dentist .desi .design .dev .dhl .diamonds .diet .digital .direct .directory .discount .discover .dish .diy .dj .dk .dm .dnp .do .docs .doctor .dog .domains .dot .download .drive .dtv .dubai .dunlop .dupont .durban .dvag .dvr .dz .earth .eat .ec .eco .edeka .edu .education .ee .eg .email .emerck .energy .engineer .engineering .enterprises .epson .equipment .er .ericsson .erni .es .esq .estate .et .eu .eurovision .eus .events .exchange .expert .exposed .express .extraspace .fage .fail .fairwinds .faith .family .fan .fans .farm .farmers .fashion .fast .fedex .feedback .ferrari .ferrero .fi .fidelity .fido .film .final .finance .financial .fire .firestone .firmdale .fish .fishing .fit .fitness .fj .fk .flickr .flights .flir .florist .flowers .fly .fm .fo .foo .food .football .ford .forex .forsale .forum .foundation .fox .fr .free .fresenius .frl .frogans .frontier .ftr .fujitsu .fun .fund .furniture .futbol .fyi .ga .gal .gallery .gallo .gallup .game .games .gap .garden .gay .gb .gbiz .gd .gdn .ge .gea .gent .genting .george .gf .gg .ggee .gh .gi .gift .gifts .gives .giving .gl .glass .gle .global .globo .gm .gmail .gmbh .gmo .gmx .gn .godaddy .gold .goldpoint .golf .goo .goodyear .goog .google .gop .got .gov .gp .gq .gr .grainger .graphics .gratis .green .gripe .grocery .group .gs .gt .gu .gucci .guge .guide .guitars .guru .gw .gy .hair .hamburg .hangout .haus .hbo .hdfc .hdfcbank .health .healthcare .help .helsinki .here .hermes .hiphop .hisamitsu .hitachi .hiv .hk .hkt .hm .hn .hockey .holdings .holiday .homedepot .homegoods .homes .homesense .honda .horse .hospital .host .hosting .hot .hotels .hotmail .house .how .hr .hsbc .ht .hu .hughes .hyatt .hyundai .ibm .icbc .ice .icu .id .ie .ieee .ifm .ikano .il .im .imamat .imdb .immo .immobilien .in .inc .industries .infiniti .info .ing .ink .institute .insurance .insure .int .international .intuit .investments .io .ipiranga .iq .ir .irish .is .ismaili .ist .istanbul .it .itau .itv .jaguar .java .jcb .je .jeep .jetzt .jewelry .jio .jll .jm .jmp .jnj .jo .jobs .joburg .jot .joy .jp .jpmorgan .jprs .juegos .juniper .kaufen .kddi .ke .kerryhotels .kerrylogistics .kerryproperties .kfh .kg .kh .ki .kia .kids .kim .kindle .kitchen .kiwi .km .kn .koeln .komatsu .kosher .kp .kpmg .kpn .kr .krd .kred .kuokgroup .kw .ky .kyoto .kz .la .lacaixa .lamborghini .lamer .lancaster .land .landrover .lanxess .lasalle .lat .latino .latrobe .law .lawyer .lb .lc .lds .lease .leclerc .lefrak .legal .lego .lexus .lgbt .li .lidl .life .lifeinsurance .lifestyle .lighting .like .lilly .limited .limo .lincoln .link .lipsy .live .living .lk .llc .llp .loan .loans .locker .locus .lol .london .lotte .lotto .love .lpl .lplfinancial .lr .ls .lt .ltd .ltda .lu .lundbeck .luxe .luxury .lv .ly .ma .madrid .maif .maison .makeup .man .management .mango .map .market .marketing .markets .marriott .marshalls .mattel .mba .mc .mckinsey .md .me .med .media .meet .melbourne .meme .memorial .men .menu .merckmsd .mg .mh .miami .microsoft .mil .mini .mint .mit .mitsubishi .mk .ml .mlb .mls .mm .mma .mn .mo .mobi .mobile .moda .moe .moi .mom .monash .money .monster .mormon .mortgage .moscow .moto .motorcycles .mov .movie .mp .mq .mr .ms .msd .mt .mtn .mtr .mu .museum .music .mv .mw .mx .my .mz .na .nab .nagoya .name .natura .navy .nba .nc .ne .nec .net .netbank .netflix .network .neustar .new .news .next .nextdirect .nexus .nf .nfl .ng .ngo .nhk .ni .nico .nike .nikon .ninja .nissan .nissay .nl .no .nokia .norton .now .nowruz .nowtv .np .nr .nra .nrw .ntt .nu .nyc .nz .obi .observer .office .okinawa .olayan .olayangroup .ollo .om .omega .one .ong .onl .online .ooo .open .oracle .orange .org .organic .origins .osaka .otsuka .ott .ovh .pa .page .panasonic .paris .pars .partners .parts .party .pay .pccw .pe .pet .pf .pfizer .pg .ph .pharmacy .phd .philips .phone .photo .photography .photos .physio .pics .pictet .pictures .pid .pin .ping .pink .pioneer .pizza .pk .pl .place .play .playstation .plumbing .plus .pm .pn .pnc .pohl .poker .politie .porn .post .pr .pramerica .praxi .press .prime .pro .prod .productions .prof .progressive .promo .properties .property .protection .pru .prudential .ps .pt .pub .pw .pwc .py .qa .qpon .quebec .quest .racing .radio .re .read .realestate .realtor .realty .recipes .red .redstone .redumbrella .rehab .reise .reisen .reit .reliance .ren .rent .rentals .repair .report .republican .rest .restaurant .review .reviews .rexroth .rich .richardli .ricoh .ril .rio .rip .ro .rocks .rodeo .rogers .room .rs .rsvp .ru .rugby .ruhr .run .rw .rwe .ryukyu .sa .saarland .safe .safety .sakura .sale .salon .samsclub .samsung .sandvik .sandvikcoromant .sanofi .sap .sarl .sas .save .saxo .sb .sbi .sbs .sc .scb .schaeffler .schmidt .scholarships .school .schule .schwarz .science .scot .sd .se .search .seat .secure .security .seek .select .sener .services .seven .sew .sex .sexy .sfr .sg .sh .shangrila .sharp .shaw .shell .shia .shiksha .shoes .shop .shopping .shouji .show .si .silk .sina .singles .site .sj .sk .ski .skin .sky .skype .sl .sling .sm .smart .smile .sn .sncf .so .soccer .social .softbank .software .sohu .solar .solutions .song .sony .soy .spa .space .sport .spot .sr .srl .ss .st .stada .staples .star .statebank .statefarm .stc .stcgroup .stockholm .storage .store .stream .studio .study .style .su .sucks .supplies .supply .support .surf .surgery .suzuki .sv .swatch .swiss .sx .sy .sydney .systems .sz .tab .taipei .talk .taobao .target .tatamotors .tatar .tattoo .tax .taxi .tc .tci .td .tdk .team .tech .technology .tel .temasek .tennis .teva .tf .tg .th .thd .theater .theatre .tiaa .tickets .tienda .tips .tires .tirol .tj .tjmaxx .tjx .tk .tkmaxx .tl .tm .tmall .tn .to .today .tokyo .tools .top .toray .toshiba .total .tours .town .toyota .toys .tr .trade .trading .training .travel .travelers .travelersinsurance .trust .trv .tt .tube .tui .tunes .tushu .tv .tvs .tw .tz .ua .ubank .ubs .ug .uk .unicom .university .uno .uol .ups .us .uy .uz .va .vacations .vana .vanguard .vc .ve .vegas .ventures .verisign .versicherung .vet .vg .vi .viajes .video .vig .viking .villas .vin .vip .virgin .visa .vision .viva .vivo .vlaanderen .vn .vodka .volvo .vote .voting .voto .voyage .vu .wales .walmart .walter .wang .wanggou .watch .watches .weather .weatherchannel .webcam .weber .website .wed .wedding .weibo .weir .wf .whoswho .wien .wiki .williamhill .win .windows .wine .winners .wme .wolterskluwer .woodside .work .works .world .wow .ws .wtc .wtf .xbox .xerox .xihuan .xin .xxx .xyz .yachts .yahoo .yamaxun .yandex .ye .yodobashi .yoga .yokohama .you .youtube .yt .yun .za .zappos .zara .zero .zip .zm .zone .zuerich .zw
lengthcount
2248
3216
4206
5156
6160
7124
879
943
1030
1121
124
133
143
153
181

Punycode

DNS requires ASCII-only. However, the Punycode encoding scheme allows for domains in all languages, e.g., Chinese, Arabic, Hindi, etc.

Here are several examples.

Reserved

Reserved DomainSays Who
.exampleRFC 6761
.example.comRFC 6761
.example.netRFC 6761
.example.orgRFC 6761
.invalidRFC 6761
.localhostRFC 6761
.testRFC 6761
.localRFC 6762
.onionRFC 7686

There are also reserved IP addresses.