Do I really need an MX record? (for e-mail to work)

[Peter Dambier]

sm5w2 at hotmail.com wrote:
> Because of a recent change to our internet connection, I discovered
> that our MX record has been essentially non-existant for the past 2 or
> 3 weeks.  Our A record is fine.
> 
> It's easy enough to configure our MX record, but I'm reluctant to do so
> because:
> 
> 1) We are getting e-mail, and there is no indication that anyone trying
> to send us e-mail is encountering any difficulty

I remember originally I sent and received email using /etc/hosts only,
no DNS at all. Later with DNS it still worked without MX records but
there were somany sites that I could not send email to.

> 
> 2) The lack of an MX record seems to result in a fall-back to the A
> record (which explains why we are getting e-mail).

I see MX as kind of a CNAME record. It is an A record after all that
says where your mail should go.

> 3) I've noticed a huge reduction in the amount of "zombie" or trojan
> spam being received by several of our well known addresses.
> 

Only after I had my MX record in place and a lot of other things in sync
with each other I was able to send email to mostly all sites.

> Because of all three of the above (especially item 3) I think I'll be
> letting this experiment go a while longer and see if not having an MX
> record turns out to be a great way to prevent spam from finding us.
> 

It is only 3) that makes a difference. How about your outgoing mails?


I can imagine some spammers digging for MX records. But they still
must know a user. How about a user "*" that get all mail that does
not find a valid user, and sending this mail silently to the bin?

> Anyone care to comment?
> 
> ps:  There seems to be no SMTP-specific newsgroup for talking about the
> benefits and pitfalls of not having an MX record (and no, NANAE does
> not seem relavent).  Are there any web forums for SMTP discussions?
> 
> 

There is an anti spam wg at ripe I believe.


Regards
Peter and Karin


-- 
Peter and Karin Dambier
The Public-Root Consortium
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mail: peter at peter-dambier.de
mail: peter at echnaton.serveftp.com
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