url - RFC 1738 : URL: Must the host contain a dot?

Question

根据 RFC 1738: Uniform Resource Locators (URL): 3.1. Common Internet Scheme Syntax ，宿主组件是否必须包含一个点，例如“example.com”？即，它可以只由一个域标签组成吗？

Answer 1

不，主机不必包含点。即，是的，只有一个域标签就可以了。看 domain , subdomain和 label ( http://tools.ietf.org/html/rfc1034#section-3.5 ):

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

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

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

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

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

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

<letter> ::= any one of the 52 alphabetic characters A through Z in upper case and a through z in lower case

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

本文档引用自 http://tools.ietf.org/html/rfc1738#section-3.1描述主机命名规则。