Just a case in point take a look at my address.

Now I do have a MX record (by neccessity) and I'm sure voicenet.com
(my isp) has a MX record, I'm also fairly sure ml.org has a MX record.
Now if you try to lookup a MX record for doyl255-pri.voicenet.com (one of
the ip's I could be assigned) you won't find one. Greg, which one of these
would you be checking?

Just my five cents.

On Mon, 6 Jul 1998, John Nemeth wrote:

[snip]
> } A tremendously large number of A RRs in the DNS point at dial-up hosts
> 
>      Yeah, so.
> 
> } which do not (and cannot, by definition, if they are dynamically
> } assigned) run SMTP servers.  If an SMTP client were to use such an A RR
> 
>      This statement is completely false.  There is absolutely nothing
> to stop a dial-up host from running an SMTP server.  However, they
> either have to have a static address (some very large ISP's only give
> out static addresses), or use some form of dynamic IP, if they expect
> to have reliable mail reception.
> 
> } in their SMTP sender envelope address to any receiving SMTP other than
> } their own locally authorized outgoing SMTP relay gateway, then it will
> } be impossible to return any mail to them.  At least with a valid MX
> 
>      Really?!?  I suggest you check out ml.org and dynip.com, which
> are just two organisations that offer dynamic IP addresses.
> Furthmore, IPv6, which is just arround the corner, officially endorses
> dynamic IP addresses.  Also check out demon.com, which is the largest
> ISP in Europe, they only give out static addresses.
> 
> } there's a far better chance that the assumption a connection to the SMTP
> } port at the destination MX host will succeed.
> 
[snip]
> 
> }-- End of excerpt from Greg A. Woods
>