[comp.mail.sendmail] Using numerical addresses

srf@claudius.juliet.ll.mit.edu ( Steve Feinstein) (04/05/91)

Is it possible to send mail using numerical addresses instead
of domain names?  Our yp hosts database is far from complete and
rather than constantly asking our sys admin to add names to it, I'd
like to be able to send mail based on the numerical address.  I
tried aliasing some names but it didn't work.  The mailer-daemon
still complained that the host was unknown.  Is there a way to 
do this?  Thanks in advance for all responses.

--

		Steve Feinstein

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simon@opal.CS.TU-Berlin.DE (Simon Leinen) (04/09/91)

>>>>> On 5 Apr 91 14:56:53 GMT, srf@claudius.juliet.ll.mit.edu ( Steve
>>>>> Feinstein) said:

Steve> Is it possible to send mail using numerical addresses instead
Steve> of domain names?

From RFC 821 (Simple Mail Transfer Protocol):

	 ... One form is a decimal integer prefixed by a pound sign,
	 "#", which indicates the number is the address of the host.
	 Another form is four small decimal integers separated by dots
	 and enclosed by brackets, e.g., "[123.255.37.2]", which
	 indicates a 32-bit ARPA Internet Address in four 8-bit
	 fields.

So you can probably use addresses of the form simon@[192.35.149.176]
(works for me).

Steve> Our yp hosts database is far from complete and rather than
Steve> constantly asking our sys admin to add names to it, I'd like to
Steve> be able to send mail based on the numerical address.

The correct solution to your problems would be to use the Domain Name
System.  This is something like a huge distributed database that
transparently maps (among other things) qualified hostnames to
IP-addresses by querying different name servers on the Internet.
-- 
Simon.
Internet: simon@[192.35.149.176]
	  simon@Opal.CS.TU-Berlin.DE