At 02:51 22-08-2005, Willemien wrote:
[[ added requirements]]
For the purposes of this specification, a host is a computer system
attached to the Internet (or, in some cases, to a private TCP/IP network)
and supporting the SMTP protocol. Hosts are known by names (see the next
section); they SHOULD NOT be identified by numerical address.
Fully capable SMTP systems MUST conform to the following requirements:
For fully capable SMTP Clients:
The hostname given in the EHLO or HELO command MUST resolve in a DNS A
SMTP clients behind a NAT may not be able to follow this requirement
(see RFC 2821 section 4.1.3).
That A record MUST point to the SMTP Client.
And the IP address of the SMTP client MUST resolve back to the hostname.
That may not be possible with multi-homing.