⸻⸻ ★ ★ ★ ★ ★ ★ ★ ★ ★ ⸻⸻

Basically

1 (page 9) ● 2 (38 allowed characters) ● 3 (page 3 > point 4) ● 4 (> IETF Standards)

All characters that the DNS can process 

for the formation of domain names are the following 38 ASCII characters:

-.0123456789abcdefghijklmnopqrstuvwxyz

(represented in ASCII order)

If it is an IDN (Internationalized Domain Name), a domain name 

which contains non-ASCII characters (for example xð.com), the non-ASCII characters 

are always automatically converted into a puny code (for example the puny code for xð.com is xn--x-pga.com), which in the end consists only of ASCII characters and 

always begins with xn--), so that the DNS can process the IDN.

This shows that in the end 

there are always and only ASCII characters in DNS 

for the formation of domain names. 

Therefore, the 38 ASCII characters listed above can be called 

the elixir or the basic substance of all domain names.

However, due to the rules in the DNS, 

these 38 ASCII characters cannot be represented exactly 1:1 in the ASCII order (like listed above) in a or as a DOMAIN NAME. The correct order of the 38 characters IN OR AS A DOMAIN NAME therefore results from the best possible adherence to the ASCII order, which is possible in the DNS and looks as follows:

0-123456789abcdefghijklmnopqrstuvw.xyz

[ULTIMATE DOMAIN NAME - the SHORTEST

(SHORTEST Domain Name With All Characters In Correct Order)]

Below you can see the step-by-step construction plan 

of the ULTIMATE DOMAIN NAME*.

[As the ULTIMATE DOMAIN NAME* consists of 2** versions (SHORTEST and LONGEST) you will found 2 step-by-step construction plans, each for every version. 

First the SHORTEST version [ULTIMATE DOMAIN NAME - the SHORTEST

(SHORTEST Domain Name With All Characters In Correct Order)] and then the LONGEST version [ULTIMATE DOMAIN NAME - the LONGEST

(LONGEST Domain Name With All Characters In Correct Order)], 

ok, lets start:

Step-by-step 

construction plan for the

ULTIMATE DOMAIN NAME - the SHORTEST

(SHORTEST Domain Name With All Characters In Correct Order)

As you can see above, the 1st of the 38 ASCII characters in the correct order (ASCII order) is the hyphen (-). However, due to DNS rules, a domain name cannot begin or end with a hyphen, so the next possible character in the ASCII order is used for the beginning of the domain name, which is the following:

0 (zero)

Therefore, the following characters remain (represented in ASCII order):

-.123456789abcdefghijklmnopqrstuvwxyz

Now the hyphen, the next of the remaining characters in the ASCII order, is already possible:

0-

Therefore, the following characters remain (represented in ASCII order):

.123456789abcdefghijklmnopqrstuvwxyz

According to the ASCII order, the dot (.) would actually come now, 

but due to the DNS rules it cannot be placed after a hyphen.

The next possible character in the ASCII order is therefore the number 1:

0-1

Therefore, the following characters remain (represented in ASCII order):

.23456789abcdefghijklmnopqrstuvwxyz

According to the ASCII order, the dot would actually come now, which also would now be possible according to the DNS rules but is not yet possible due to the required placement of the other characters (23456789abcdefghijklmnopqrstuvwxyz) in the domain name, as the dot (.) only acts as a boundary or separator between the different domain levels, in this case between SLD and TLD. And as there is no "23456789abcdefghijklmnopqrstuvwxyz" TLD, the next character in the ASCII sequence is therefore the number 2:

0-12

Therefore, the following characters remain (represented in ASCII order):

.3456789abcdefghijklmnopqrstuvwxyz

Now the same is valid as after 0-1 etc. up to and including the letter w, so it results in:

0-123456789abcdefghijklmnopqrstuvw

Therefore, the following characters remain (represented in ASCII order):

Since .xyz is a TLD (NUMBER 1 NEW TLD 🡸 .XYZ 🡺 SMARTEST NEW TLD) and all other characters are already accommodated, the dot along wit xyz is now possible, which results since 2023-01-01 in the ULTIMATE DOMAIN NAME - the SHORTEST

(SHORTEST Domain Name With All Characters In Correct Order):

0-123456789abcdefghijklmnopqrstuvw.xyz

And here is 

the Step-by-step 

construction plan for the

ULTIMATE DOMAIN NAME - the LONGEST

(LONGEST Domain Name With All Characters In Correct Order)

Basically   →   -1-   -2-   -3-

As it is the ULTIMATE DOMAIN NAME - the LONGEST (LONGEST Domain Name With All Characters In Correct Order), it of course does not consist of the minimum number (38) of characters required for the ULTIMATE DOMAIN NAME - the SHORTEST (SHORTEST Domain Name With All Characters In Correct Order), but, as expected, of the maximum number (253) of characters ULTIMATE DOMAIN NAME - the LONGEST (LONGEST Domain Name With All Characters In Correct Order).

This means that in addition to the 38 different ASCII characters, there are 212 additional hyphens (in this case the only PERFECT choice to achieve the MAXIMUM length of the domain name) and 3 additional dots (in this case the only PERFECT, automatically resulting 'choice' to achieve the MAXIMUM length of the domain name).

Since only 253 characters are possible in total, the SLD has only 57 characters and not 63 characters (like the subdomains) and since the hyphen always comes before a number or a letter according to the ASCII order, the subdomain on the far left, i.e. the one that starts with 0 (zero), has 63 characters and not the SLD, which ends with w. Everything has a reason and is structured according to a well thought-out blueprint.

But now let's get started:

The characters for the formation of the ULTIMATE DOMAIN NAME - the LONGEST

(LONGEST Domain Name With All Characters In Correct Order) are the following (represented in ASCII order):

 ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------....0123456789abcdefghijklmnopqrstuvwxyz 

However, due to the rules in the DNS, these 253 characters cannot be represented exactly 1:1 in the ASCII order (like listed above) in a or as a DOMAIN NAME.

The correct order of the 253 characters IN OR AS A DOMAIN NAME therefore results from the best possible adherence to the ASCII order, which is possible in the DNS and looks as follows:

 0-------------------------------------------------------------1.2-------------------------------------------------------------3.4-------------------------------------------------------------5.6--7----------------------------89abcdefghijklmnopqrstuvw.xyz 

[ULTIMATE DOMAIN NAME - the LONGEST

(LONGEST Domain Name With All Characters In Correct Order)]

As you already know, the 1st of the ASCII characters in the correct order (ASCII order) is the hyphen (-). However, due to DNS rules, a domain name cannot begin or end with a hyphen, so the next possible character in the ASCII order is used for the beginning of the ULTIMATE DOMAIN NAME - the LONGEST (LONGEST Domain Name With All Characters In Correct Order), which is the following:

0 (zero)

Therefore, the following characters remain (represented in ASCII order):

-------------------------------------------------------------1.2-------------------------------------------------------------3.4-------------------------------------------------------------5.6--7----------------------------89abcdefghijklmnopqrstuvw.xyz

Now the hyphen, the next of the remaining characters in the ASCII order, is already 61 times possible:

0-------------------------------------------------------------

Therefore, the following characters remain (represented in ASCII order):

--------------------------------------------------------------------------------------------------------------------------------------------------------....123456789abcdefghijklmnopqrstuvwxyz

Due to the limited number of 63 characters per domain level (which is always separated by the dot), and due to the fact that no hyphen is possible before and after the dot, the number 1 is now the next possible character in the correct order:

0-------------------------------------------------------------1

Therefore, the following characters remain (represented in ASCII order):

--------------------------------------------------------------------------------------------------------------------------------------------------------....23456789abcdefghijklmnopqrstuvwxyz

The next character in the correct order would now be the hyphen, but as already explained, this is not possible due to the limited number of 63 characters per domain level. And as 0-------------------------------------------------------------1 already reached 63 characters, there must be a dot now, therefore:

0-------------------------------------------------------------1.

The whole process is now repeated, of course with different digits and in the correct order, taking into account the DNS rules (otherwise it is not possible anyway), until only the Second Level Domain (SLD) and the Top Level Domain (TLD) remain to be formed:

0-------------------------------------------------------------1.2-------------------------------------------------------------3.4-------------------------------------------------------------5.

Therefore, the following characters remain (represented in ASCII order):

------------------------------.6789abcdefghijklmnopqrstuvwxyz

Now logically comes the digit 6 and then hyphens again, but be careful: Only 2 hyphens! Due to the DNS rules for Internationalized Domain Names (IDN), the 3rd position in combination with the 4th position cannot be used for non-IDN domain names, as these two positions are always reserved for the punycode of the IDN name. This means that after the two hyphens comes the next character in the correct order, which is the number 7:

0-------------------------------------------------------------1.2-------------------------------------------------------------3.4-------------------------------------------------------------5.6--7

Therefore, the following characters remain (represented in ASCII order):

----------------------------.89abcdefghijklmnopqrstuvwxyz

Now hyphens are possible again, all those that can still be installed, so the remaining 28 hyphens are added:

0-------------------------------------------------------------1.2-------------------------------------------------------------3.4-------------------------------------------------------------5.6--7----------------------------

Therefore, the following characters remain (represented in ASCII order):

.89abcdefghijklmnopqrstuvwxyz

As you can see, according to the ASCII order, the dot would now come, but this is not possible due to the DNS rules, so the next possible character comes in the correct order, which is the number 8, and to shorten it a little, we take the next character according to the correct order - the number 9 - right along with it:

0-------------------------------------------------------------1.2-------------------------------------------------------------3.4-------------------------------------------------------------5.6--7----------------------------89

Therefore, the following characters remain (represented in ASCII order):

.abcdefghijklmnopqrstuvwxyz

Since .xyz is a TLD (NUMBER 1 NEW TLD 🡸 .XYZ 🡺 SMARTEST NEW TLD), abcdefghijklmnopqrstuvw is now added after the 9:

0-------------------------------------------------------------1.2-------------------------------------------------------------3.4-------------------------------------------------------------5.6--7----------------------------89abcdefghijklmnopqrstuvw

The following characters therefore remain (represented in ASCII order):

Taking into account the best possible compliance with all specifications (ASCII order / DNS rules / STRUCTURE of the domain name), the ULTIMATE DOMAIN NAME - the LONGEST (LONGEST Domain Name With All Characters In Correct Order) was created on 2022-09-21 by setting the .xyz TLD:

0-------------------------------------------------------------1.2-------------------------------------------------------------3.4-------------------------------------------------------------5.6--7----------------------------89abcdefghijklmnopqrstuvw.xyz