discuss Theoretical number of domains available to register

[CraigD]

Here's a question for budding mathematicians.

It would be interesting to know if someone can do the calculations to figure out the theoretical number of domain names that can be registered in the .COM TLD

Perhaps you can also do the math for all the domain extensions currently available?

I imagine this number would be greater than all the grains of sand on all the worlds...

What is your guess?

 

[CraigD]

This number may end with ...42

 

[lock]

Does it have to be words or just as many characters i could cram in an still register even thought 99.9% of it will have no value. I can do the math how many characters multiplied with in 64 characters.

 

[CraigD]

Does it have to be words or just as many characters i could cram in an still register even thought 99.9% of it will have no value. I can do the math how many characters multiplied with in 64 characters.

No it's a lot more complex than that. You have available numbers and characters, how many are actually used, permutations etc.
Some extensions also utilise special or language characters.

 

[lock]

yes but only 64 characters to work with.

 

[CraigD]

yes but only 64 characters to work with.

So for a TLD, a domain name can be up to 63 characters (letters, numbers or combination) long. The only symbol character domain names can include is a hyphen (-) although the domain name cannot start or end with a hyphen nor have consecutive hyphens.

 

[koolishman]

yes but only 64 characters to work with.

That is the catch.

Hope someone cracks it.

 

[lock]

This number may end with ...42

then separate those 2 numbers add them together subtract one.
then think of an animal starting with the letter if a =1 b=2 c=3 d=4 e=5
think of a color of the animal.
think of a country starting with d
now we are talking about
grey elephants in delhi.

 

[Jurgen Wolf]

https://en.wikipedia.org/wiki/Domain_Name_System#Domain_name_syntax,_internationalization

 

[lock]

need to know how many - wggly wingding emog things register.

 

[CraigD]

need to know how many - wggly wingding emog things register.

Edit: I think Unicode, Punicode is translated by ASCII as referenced by the link that @Jurgen Wolf posted above

 

[CraigD]

"An additional rule requires that top-level domain names should not be all-numeric"
Is that still the case?

 

[lock]

Numbers only have been around ages and first were popular with icq numbers as dot coms.

 

[bmugford]

Well, without any special characters or hyphens, it would be 36 to the 64th power, which is a number so large I doubt any person (outside a genius mathematician) could recognize it.

The basic math is there are 26 letters and 10 numbers possible. There are 36 unique options in each slot. There are max 64 slots.

When you start factoring in special characters the number would get far larger.

Brad

 

[lock]

Once the total amount of different characters is established i will attempt it.

 

[CraigD]

Well, without any special characters or hyphens, it would be 36 to the 64th power, which is a number so large I doubt any person (outside a genius mathematician) could recognize it.

The basic math is there are 26 letters and 10 numbers possible. There are 36 unique options in each slot. There are max 64 slots.

When you start factoring in special characters the number would get far larger.

Brad

Plus there are the special rules to observe about hyphens that complicates issues.

 

[lock]

eg to make up an idn special characters screw up equation even more variables.

 

[Paul]

Here's a question for budding mathematicians.

It would be interesting to know if someone can do the calculations to figure out the theoretical number of domain names that can be registered in the .COM TLD

Perhaps you can also do the math for all the domain extensions currently available?

I imagine this number would be greater than all the grains of sand on all the worlds...

What is your guess?

I'm ignoring the following facts in the calculations:

1. The IDN system imposes additional restrictions on labels beginning with xn--, resulting in a reduction in the number of possible labels.
2. Registries can impose arbitrary rules on domain registrations.
3. In some cases, there are conflicting rules for domain names. For example, RFC 1035 2.3.1 forbids labels that begin with a digit, but the existence of 163.com proves that .com doesn't adhere to that rule. (RFC 1035 is one of the oldest relevant RFCs, and many have come after it that make changes.)
4. DNS can technically encode labels that contain arbitrary octets. However, common implementations only permit ASCII A-Z, a-z, 0-9, - (hyphen), and _ (underscore). Furthermore, A-Z and a-z are treated as equivalent. Since octets representing other characters would be unusual and present compatibility issues, I'm ignoring those.
5. Some systems may impose restrictions on the first and/or last character of a label. I'm ignoring those.

Note that IDNs don't increase the number of possible domains--instead, IDNs decrease the number of possible domains. All IDNs have to be encoded to ASCII for use in DNS; that encoded form, Punycode, is subject to the same restrictions as non-IDNs. However, for a system to support Punycode, it has to impose additional restrictions on label beginning with xn--, thereby decreasing the number of possible labels.

Per character, that gives us 39 possibilities:

• 26: A-Z
• 10: 0-9
• 1: -
• 1: _

Labels can be up to 63 characters in DNS--that's the maximum length that can be encoded. Thus, for each length, we get:

• Length of 1: 39 possibilities
• Length of 2: 39^2 possibilities
• ...
• Length of 62: 39^62 possibilities
• Length of 63: 39^63 possibilities

If we sum those all up, we get 17715411840326414139418181731112699586559651152219815288474011280746308525590734354933147461703118079 possibilities for a single label. Conveniently, that's about 1.8 googol--just for a single TLD. If you're planning on registering that many domains, you might run into some difficulties.

 

[CraigD]

So essentially, registrar potential earnings are almost infinite.

 

[lock]

nerd @Paul thanks for your post. geeking out hard.

 

[CraigD]

nerd @Paul thanks for your post. geeking out hard.

Thanks @Paul - trust the CTO of NamePros to roughly figure this out

 

[RogueWriter]

I'm ignoring the following facts in the calculations:

1. The IDN system imposes additional restrictions on labels beginning with xn--, resulting in a reduction in the number of possible labels.
2. Registries can impose arbitrary rules on domain registrations.
3. In some cases, there are conflicting rules for domain names. For example, RFC 1035 2.3.1 forbids labels that begin with a digit, but the existence of 163.com proves that .com doesn't adhere to that rule. (RFC 1035 is one of the oldest relevant RFCs, and many have come after it that make changes.)
4. DNS can technically encode labels that contain arbitrary octets. However, common implementations only permit ASCII A-Z, a-z, 0-9, - (hyphen), and _ (underscore). Furthermore, A-Z and a-z are treated as equivalent. Since octets representing other characters would be unusual and present compatibility issues, I'm ignoring those.
5. Some systems may impose restrictions on the first and/or last character of a label. I'm ignoring those.

Note that IDNs don't increase the number of possible domains--instead, IDNs decrease the number of possible domains. All IDNs have to be encoded to ASCII for use in DNS; that encoded form, Punycode, is subject to the same restrictions as non-IDNs. However, for a system to support Punycode, it has to impose additional restrictions on label beginning with xn--, thereby decreasing the number of possible labels.

Per character, that gives us 39 possibilities:

• 26: A-Z
• 10: 0-9
• 1: -
• 1: _

Labels can be up to 63 characters in DNS--that's the maximum length that can be encoded. Thus, for each length, we get:

• Length of 1: 39 possibilities
• Length of 2: 39^2 possibilities
• ...
• Length of 62: 39^62 possibilities
• Length of 63: 39^63 possibilities

If we sum those all up, we get 17715411840326414139418181731112699586559651152219815288474011280746308525590734354933147461703118079 possibilities for a single label. Conveniently, that's about 1.8 googol--just for a single TLD. If you're planning on registering that many domains, you might run into some difficulties.

I'm.....going to take your word on it lol.
Nice reply.

 

[CraigD]

So from the rough calculations by @Paul the number for just a single TLD is much larger than all the subatomic particles in the known universe.

 

[TheBaldOne]

So if we think about this another way, so far between all of us domain owners we have only registered just circa.:

0.00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001% of all the .com domains available! (Disclaimer - I may have miscounted a '0')

Hell's Bells - we had better get our skates on!

 

[Tom_Collins]

who gives a shit how many domains can be registered as long as one gets a nice one.