send e-mail without use sendmail

[Tony Nelson]

At 8:41 PM -0600 10/31/07, Frank Cox wrote:
>On Wed, 31 Oct 2007 12:05:11 -0500
>Les Mikesell <lesmikesell at gmail.com> wrote:
>
>> You must have a real domain name to send email.
>
>Is there any technical reason (other than "we hate spammers") why email can't
>be sent to an IP address instead of a domain name?
>
>I know that mail sent to joeblow at 123.456.789.001 doesn't work, but have never
>really understood why...

It is legal to address email to an IP address for the domain name, but
discouraged by RFC 2821.  Most mailservers will reject the mail by "policy"
(in this case, anti-spam policy), which is a legal way to violate the RFC
2821 standard.  See the word "policy" throughout RFC 2821 and also sections
(retyped):

4.1.2 Command Argument Syntax
 ...
    Domain = (sub-domain 1*("." sub-domain)) / address-literal
 ...

4.1.3 Address Literals
Sometimes a host is not knwn to the domain name system and communication
(and, in particular, communication to report and repair the error) is
blocked.  To bypass this barrier a special literal form of the address is
allwed as an alternative to a domain name. ...enclosed by brackets such as
[123.255.37.2]...
 ...
-- 
____________________________________________________________________
TonyN.:'                       <mailto:tonynelson at georgeanelson.com>
      '                              <http://www.georgeanelson.com/>