电子邮件地址中是否有下划线？ [英] Leading underscores in an email address?

问题描述

我将使用什么RFC来确定是否可以接受电子邮件地址本地部分中的前导下划线？

What RFC would I refer to in order to find out if a leading underscore in the local part of an email address is acceptable?

示例： [e-mail]

当然，这个问题也适用于任何主要的特殊字符。

Of course, this question can also apply to any leading special character.

我在Wikipedia中找到了这一行，但是在RFC本身中找不到任何引用。我在这里错过了什么吗？

I found this line in Wikipedia, but couldn't find any reference within the RFC itself. Did I miss something here?

本地部分
电子邮件地址的本地部分可以使用以下任何ASCII字符RFC 5322第3.2节。 3：

推荐答案

引用RFC5322。

部分3.4.1说：

An addr-spec is a specific Internet identifier that contains a
locally interpreted string followed by the at-sign character ("@",
ASCII value 64) followed by an Internet domain.  The locally
interpreted string is either a quoted-string or a dot-atom.

回到3.2.3，您会得到：

Going back to 3.2.3 you get:

atext       =   ALPHA / DIGIT /    ; Printable US-ASCII
                   "!" / "#" /        ;  characters not including
                   "$" / "%" /        ;  specials.  Used for atoms.
                   "&" / "'" /
                   "*" / "+" /
                   "-" / "/" /
                   "=" / "?" /
                   "^" / "_" /
                   "`" / "{" /
                   "|" / "}" /
                   "~"

atom           =   [CFWS] 1*atext [CFWS]

dot-atom-text  =   1*atext *("." 1*atext)

dot-atom       =   [CFWS] dot-atom-text [CFWS]

[CFWS]表示注释或空格。

[CFWS] means comment or whitespace.

因此，电子邮件地址的第一部分可以是点原子，而后者又是

So the first part of an email address can be a dot-atom, which in turn begins with an atext, which can be an underscore.

是的，电子邮件地址可以以下划线开头。

Yes, an email address can begin with an underscore.

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