Domain hacks with unusual Unicode characters

Unicode contains a range of symbols which don't get much use. For example, there are separate symbols for TradeMark - ™, Service Mark - ℠, and Prescriptions - ℞.

Nestling among the "Letterlike Symbols" are two curious entries. Both of these are single characters:

Telephone symbol - ℡
Numero Sign - №

What's interesting is both .tel and .no are Top-Level-Domains (TLD) on the Domain Name System (DNS).

So my contact site - https://edent.tel/ - can be written as - https://edent.℡/

And the Norwegian domain name registry NORID can be accessed at https://www.norid.№/

Copy and paste those links - they work in any browser!

Is this limited to TLDs?

No! This works ANYWHERE in a domain name. Copy and paste these examples:

Script https://ℰ𝒳𝒜ℳ𝓟ℒℰ.𝒞𝓞ℳ/
Math Bold https://𝐞𝐱𝐚𝐦𝐩𝐥𝐞.𝐜𝐨𝐦/
Fraktur https://𝖊𝖝𝖆𝖒𝖕𝖑𝖊.𝖈𝖔𝖒/
Math bold italic https://𝒆𝒙𝒂𝒎𝒑𝒍𝒆.𝒄𝒐𝒎/
Math bold script https://𝓮𝔁𝓪𝓶𝓹𝓵𝓮.𝓬𝓸𝓶/
Double struck https://𝕖𝕩𝕒𝕞𝕡𝕝𝕖.𝕔𝕠𝕞/
Monospace https://𝚎𝚡𝚊𝚖𝚙𝚕𝚎.𝚌𝚘𝚖/
Super script https://ᵉˣᵃᵐᵖˡᵉ.ᶜᵒᵐ/
Sub script https://ₑₓₐₘₚₗₑ.cₒₘ/ NB not all characters supported
Math sans bold https://𝗲𝘅𝗮𝗺𝗽𝗹𝗲.𝗰𝗼𝗺/
Math sans bold italic https://𝙚𝙭𝙖𝙢𝙥𝙡𝙚.𝙘𝙤𝙢/
Math sans italic https://𝘦𝘹𝘢𝘮𝘱𝘭𝘦.𝘤𝘰𝘮/
Math Squared https://🄴🅇🄰🄼🄿🄻🄴.🄲🄾🄼/ NB the dot must not be squared
Circled https://ⓔⓧⓐⓜⓟⓛⓔ.ⓒⓞⓜ/ NB the dot must not be circled

There are a whole bunch more miscellaneous characters you can use:

How does this work?

Magic! Which is to say, I think it is the browser doing the conversion. DNS Servers don't successfully reply to queries about .℡ domains.

The browser sees the .℡ and then follows the IDNA2008 process listed in RFC5895 to normalise it:

map characters to the "Simple_Lowercase_Mapping" property (the fourteenth column) in <http://www.unicode.org/Public/UNIDATA/UnicodeData.txt>, if any.

The ℡ entry is:

2121;TELEPHONE SIGN;So;0;ON;<compat> 0054 0045 004C;;;;N;T E L SYMBOL;;;;

U+0054 is T, U+0045 is E, U+004C is L.

You can test this in Python using:

python -c 'import sys;print sys.argv[1].decode("utf-8").encode("idna")' "℡"

Does this work?

Yes! I asked people on Twitter whether they could access my website using a .℡ - and it appeared to work on every modern browser and operating system.

It even works on command line tools like wget and curl.

It does fail in some circumstances:

What are the limitations?

Two main ones:

Sites like Twitter and Facebook don't recognise it as a valid URl and refuse to auto link it.
Some command line tools like dig and host don't understand it

 Bashdig edent.℡

; <<>> DiG 9.10.6 <<>> edent.℡
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 55282

Obviously yes. This may be the most important discovery of the decade. You get cool looking URls and get to save a couple of characters on specific domains, at the minor expense of working inconsistently.

It could also be used for evading URl filters.

Every modern browser supports these "fancy" domain names - but most websites won't automatically link to them. So sharing on Facebook doesn't work.

Where can it be used?

Here are the single characters which can be normalised down to a valid TLD. They're mostly country codes, but there are a few interesting exceptions:

㏕ - US Military
℡ - .tel registry
№ - Norway
㍳ - Australia
㍷ - Dominica
㎀ - Panama
㎁ - Namibia
㎃ - Morocco
㎊ - French Polynesia
㎋ - Norfolk Island
㎏ - Kyrgyzstan
㎖ - Mali
㎙ - Federated States of Micronesia
ﬁ - Finland
㎜ - Myanmar
㎝ - Cameroon
㎞ & ㏎ - Comoros
㎰ - Palestine
㎳ - Montserrat
㎷ & ㎹ - Republic of Maldives.
㎺ - Palau
㎽ & ㎿ - Malawi
㏄ - Cocos (Keeling) Islands
㏅ - Democratic Republic of Congo
㏉ - Guyana
㏗ - Philippines
㏘ - Saint Pierre and Miquelon
㏚ - Puerto Rico
㏛ - Suriname
㏜ - El Salvador
℠ - San Marino
™ - Turkmenistan
ﬆ & ﬅ - São Tomé and Príncipe
㎇ - Great Britain ( Obsolete)
ß - South Sudan ( Not available)
㏌ - India and Indiana (subdomain of .us)
Ⅵ & ⅵ - Virgin Islands and Virginia (subdomain of .us)
ﬂ - Florida (subdomain of .us)
㎚ - New Mexico (subdomain of .us)
㎵ - Nevada (subdomain of .us)
㍵ - As part of .ovh

If you can find any more, please stick a comment in the box below.

You can always reach this blog post at:

https://🅂𝖍𝐤ₛᵖ𝒓.ⓜ𝕠𝒃𝓲/🆆🆃🅵/

Is this limited to TLDs?

How does this work?

Does this work?

What are the limitations?

Is this useful?

Where can it be used?