[LINK] RFC: emailing to <username>@<IP-Address>

[Kim Holburn]

This is on Page 37 of http://www.ietf.org/rfc/rfc2821.txt

       address-literal = "[" IPv4-address-literal /
                             IPv6-address-literal /
                             General-address-literal "]"
             ; See section 4.1.3

Many modern email servers will simply reject this but it is part of  
the RFC.


On 2007/Dec/10, at 9:52 AM, Scott Howard wrote:

> You can - the format is   username@[1.2.3.4]
>
> Of course, there's no guarantee that the remote host is going to  
> accept the
> email - especially as it generally isn't going to know what domain  
> it's
> for...
>
>   Scott.
>
>
>
> On 12/10/07, Roger Clarke <Roger.Clarke at xamax.com.au> wrote:
>>
>> Sorry, Link Institute, but I think we've been here before.
>>
>> I just wrote to a bunch of MSc(ECommerce) candidates as follows.  If
>> there's anything gravely wrong or misleading with what I said, please
>> let me (and linkers) know.
>>
>> Thanks!
>>
>>
>> Candidate asked:
>>> Q10. Can you email to someone at their IP-address rather than their
>>> domain name?
>>
>> Roger replied:
>>
>> I said in a seminar that it is not possible to email to an IP- 
>> address.
>>
>> I base this on:
>> (1)  my reading of RFC 2821, at http://www.ietf.org/rfc/rfc2821.txt
>> (2)  never having seen an email-address that includes an IP-address
>> (3)  experiments trying to send an email to the IP-address  
>> indicated in
>> the
>>       MX-record for my own domain, i.e. Roger.Clarke at 203.20.62.11.
>>       This results in a 550 error from my IAP - 'recipient blocked'.
>>
>> (I can't find a clear statement in the RFC that it isn't possible,
>> but it's clear that the recipient is meant to be defined as a
>> 'mailbox' at a 'domain-name', and that the MX record in the
>> authoritative domain-name server is intended to provide the
>> translation from 'domain-name' to IP-address).
>>
>>
>> --
>> Roger Clarke                  http://www.anu.edu.au/people/ 
>> Roger.Clarke/
>>
>> Xamax Consultancy Pty Ltd      78 Sidaway St, Chapman ACT 2611  
>> AUSTRALIA
>>                     Tel: +61 2 6288 1472, and 6288 6916
>> mailto:Roger.Clarke at xamax.com.au                http:// 
>> www.xamax.com.au/
>>
>> Visiting Professor in Info Science & Eng  Australian National  
>> University
>> Visiting Professor in the eCommerce Program      University of  
>> Hong Kong
>> Visiting Professor in the Cyberspace Law & Policy Centre      Uni  
>> of NSW
>> _______________________________________________
>> Link mailing list
>> Link at mailman.anu.edu.au
>> http://mailman.anu.edu.au/mailman/listinfo/link
>>
> _______________________________________________
> Link mailing list
> Link at mailman.anu.edu.au
> http://mailman.anu.edu.au/mailman/listinfo/link

--
Kim Holburn
IT Network & Security Consultant
Ph: +39 06 855 4294  M: +39 3494957443
mailto:kim at holburn.net  aim://kimholburn
skype://kholburn - PGP Public Key on request

Democracy imposed from without is the severest form of tyranny.
                           -- Lloyd Biggle, Jr. Analog, Apr 1961