So what is this “terrible” point at the end of the domain name?

So what is this “terrible” point at the end of the domain name? - Some have a question after a recent post .
Who does not know and wants to know - welcome under the habrakat - brush away the dust from RFC a quarter of a century ago and conduct a small investigation of its own.

In fact, this point is simple.
According to RFC 1034 (see $ 3.1 p. 7)

  ... Since a complete
 domain name ends
 ends in a dot.  We use this property to distinguish between:

    - a character string which represents a complete domain name
      (often called "absolute").  For example, "poneria.ISI.EDU."

    - a character string that represents the starting labels of a
      domain name which is incomplete
      local software using knowledge of the local domain (often
      called "relative").  For example, "poneria" used in the
      ISI.EDU domain. </ Blockquote>

That is, the dot at the end of the domain name indicates that it is a fully qualified domain name (FQDN). If there is no point, then the name is relative. Who had to configure the DNS server - saw this point in the zone files .
')
So why do we see domain names without a dot at the end in the browser address lines?
The format Uniform Resource Locators (URL) is documented in 1994. at RFC 1738 (see $ 3.1 p.5)

 
 host
         IP address:
         address as a set of four decimal digit groups separated by
         ".".  Fully qualified domain names
         in Section 3.5 of RFC 1034 [13] and Section 2.1 of RFC 1123
         [5]: a sequence of domain labels separated by ".", Each domain
         label starting and ending
         possibly also containing "-" characters.  The rightmost domain
         label will never start with a digit, though, which
         syntactically distinguishes all domain names from the IP
         addresses.

That is, the host - always either FQDN or ip - does not provide for another standard.

As you can see, there is a link to section 3.5 of RFC 1034 , but section 3.5 describes the preferred DNS name syntax

RFC 1034 3.5 Preferred name syntax

 3.5.  Preferred name syntax

 The DNS
 for constructing domain names.  The idea is that
 The existing object can be expressed as a domain name with minimal changes.
 However, when assigning a domain name to the object, the prudent user
 will choose the name of the domain system
 rules for the object, whether these rules are published
 or implied by existing programs.

 For example, when the mailing area
 RFC-822.  When creating a new host name,
 the old rules for HOSTS.TXT should be followed.  This avoids problems
 when old software is converted to use domain names.

 The following syntax will result
 applications that use domain names (eg, mail, TELNET).

 <domain> :: = <subdomain> |  ""

 <subdomain> :: = <label> |  <subdomain> "."  <label>

 <label> :: = <letter> [[<<ldh-str>] <let-dig>]

 <ldh-str> :: = <let-dig-hyp> |  <let-dig-hypn> <ldh-str>

 <let-dig-hypn> :: = <let-dig> |  "-"

 <let-dig> :: = <letter> |  <digit>

 <letter> :: = any one of the 52 alphabetic characters through Z in
 lower case

 <digit> :: = any one of the ten digits 0 through 9

 Note that letters are allowed in domain
 names, no significance is attached to the case.  That is, two names with
 The same is spelled as identical.

 The labels must follow the rules for ARPANET host names.  They must
 start with a letter
 characters only letters, digits, and hyphen.  There are also some
 restrictions on the length.  Labels must be 63 characters or less.

 For example, the following strings identify hosts in the Internet:

 A.ISI.EDU XX.LCS.MIT.EDU SRI-NIC.ARPA

and there is not a single line about the final point in fqdn

Here, apparently, the point and lost ...

Source: https://habr.com/ru/post/173045/

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So what is this “terrible” point at the end of the domain name?

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