[RFCI-Discuss] about FQDN for our smtp servers

[Alex van den Bogaerdt]

On Wed, Apr 12, 2006 at 05:35:12AM -0400, Jeff Pang wrote:
> If I send a HELO with a resolvable FQDN but that FQDN does not point to the correct sender IP,was I right?
> For example,202.108.5.84 is one of our MTAs,whose A record is: m5-84.163.com
> Now a HELO sent from  this MTA with a FQDN as 'm6-84.163.com',I think it's not right.
> So,I think the 'resolvable FQDN' should be 'resolvable and correct FQDN'.Isn't it?

Yes, it MUST be the correct FQDN.  Your host has a name, for instance
m5-84.163.com.  It is this name that MUST be used in HELO. See RFC 1123,
section 5.2.5
 
If you would use m6-84.163.com then you are using a name that does not
exist.  This is NOT a resolvable domain, thus can never be a FQDN.

Alex