Email experts... (RFC help)

[kmfdm515]

Hi guys,

I am looking for a specific paragraph in an RFC that states what characters are allowable in email addresses - namely stating that the '&' character isn't allowed.

I found RFC 2822 - but I can't quite understand it...

This section referring to 'atoms':

3.4.1. Addr-spec specification

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. If the
string can be represented as a dot-atom (that is, it contains no
characters other than atext characters or "." surrounded by atext

characters), then the dot-atom form SHOULD be used and the
quoted-string form SHOULD NOT be used. Comments and folding white
space SHOULD NOT be used around the "@" in the addr-spec.

addr-spec = local-part "@" domain

local-part = dot-atom / quoted-string / obs-local-part

domain = dot-atom / domain-literal / obs-domain

domain-literal = [CFWS] "[" *([FWS] dcontent) [FWS] "]" [CFWS]

dcontent = dtext / quoted-pair

dtext = NO-WS-CTL / ; Non white space controls

%d33-90 / ; The rest of the US-ASCII
%d94-126 ; characters not including "[",
; "]", or "\"

The domain portion identifies the point to which the mail is
delivered. In the dot-atom form, this is interpreted as an Internet
domain name (either a host name or a mail exchanger name) as
described in [STD3, STD13, STD14]. In the domain-literal form, the
domain is interpreted as the literal Internet address of the
particular host. In both cases, how addressing is used and how
messages are transported to a particular host is covered in the mail
transport document [RFC2821]. These mechanisms are outside of the
scope of this document.

The local-part portion is a domain dependent string. In addresses,
it is simply interpreted on the particular host as a name of a
particular mailbox.


seems to be the part that explains it, but I can't see how. Can some kind techie break it down for me?

 

[su root]

RFCs are written by engineers, and not meant to be understood by anyone else

Looking at it quickly, it says that ASCII character 046 (&) is allowed in the headers:

2.2. Header Fields

Header fields are lines composed of a field name, followed by a colon
(":"), followed by a field body, and terminated by CRLF. A field
name MUST be composed of printable US-ASCII characters (i.e.,
characters that have values between 33 and 126, inclusive), except
colon. A field body may be composed of any US-ASCII characters,
except for CR and LF. However, a field body may contain CRLF when
used in header "folding" and "unfolding" as described in section
2.2.3. All field bodies MUST conform to the syntax described in
sections 3 and 4 of this standard.

And investigating your quote, it you check out "3.2.4. Atom", I follow it to mean that "atext" (which contains the & symbol) exists in both "atom" "dot-atom" and "dot-atom-text", which is allowed in the email address.

Also, I created a quick email addy containing an &, and sent myself an email. Worked fine, no errors.

 

[kmfdm515]

Ah...that makes sense...after I checked the section you mentioned it all came together. So there's many charatcers that technically are valid, but aren't permitted by a lot of mail providers because they might cause conflicts. (#,$,&,etc...)

Thanks su root...you're always so helpful.