Subject: [EAI] Colon in local-part of address spec

From: Nathan <[email-masked]>
Date: Fri, 26 Mar 2010 02:14:01 +0000

Hi All,

Apologies if this is the wrong list, however I wasn't sure where else to
turn.

If I understand RFC5322 correctly then a colon is not allowed in the
local-part of addr-spec; or in general terms to the left of the @ in an
email address.

Moving forwards, I wondered if there will be a time (possibly via
internationalisation) that this would be a valid character in the
local-part.

Further still, is anybody aware of why (technically) this is a reserved
/ special char whilst ?^#| etc are not?

I am asking because, more than anything (-ish) I would like to use a
colon in my email address, to open up a whole world of functionality.

Many Regards,

Nathan

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From: Arnt Gulbrandsen <[email-masked]>
Date: Fri, 26 Mar 2010 09:21:42 +0100

> / special char whilst ?^#| etc are not?

That's historical. Once upon a time the colon was syntax.

> colon in my email address, to open up a whole world of functionality.

I think you mould find that troublesome.

Arnt

---

From: Nathan <[email-masked]>
Date: Fri, 26 Mar 2010 08:57:59 +0000

> That's historical. Once upon a time the colon was syntax.

ty for clarifying

> I think you mould find that troublesome.

any specific reasons / thoughts?

> Arnt

regards & thanks

---

From: Arnt Gulbrandsen <[email-masked]>
Date: Fri, 26 Mar 2010 10:03:31 +0100

> any specific reasons / thoughts?

1. I have good reasons to think there's still software around that 
interprets the colon as it was once used.

2. When I used a plus sign in my address (arnt+foo@...) I often had 
problems ordering stuff from random web sites. They just wouldn't accept 
the plus, legal or not. I don't think the colon will do any better.

You might be quixotic enough to battle one of these two, but both? Not 
that I mind. If you'll battle the breakage I'll cheer.

Arnt

---

From: John C Klensin <[email-masked]>
Date: Sun, 28 Mar 2010 17:53:53 -0400

--On Friday, 26 March, 2010 02:14 +0000 Nathan
<[email-masked]> wrote:

> Hi All,
> 
> Apologies if this is the wrong list, however I wasn't sure
> where else to turn.

Try the SMTP list ([email-masked]

> If I understand RFC5322 correctly then a colon is not allowed
> in the local-part of addr-spec; or in general terms to the
> left of the @ in an email address.

That is correct.  It is part of an explicit source-routing
syntax (e.g., @host1,@host2:local-part@host3 ) which, while
deprecated, is not going to go away.  The topic has nothing to
do with i18n issues; this WG can't really change
821/822/2821/2822/5821/5822 prohibitions.

> Moving forwards, I wondered if there will be a time (possibly
> via internationalisation) that this would be a valid character
> in the local-part.

Unlikely.  See above.

> Further still, is anybody aware of why (technically) this is a
> reserved / special char whilst ?^#| etc are not?

See above
 
> I am asking because, more than anything (-ish) I would like to
> use a colon in my email address, to open up a whole world of
> functionality.

Find another character.
    john