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

[rick pim]

sm5w2 at hotmail.com writes:
 > 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.

 > 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.

unfortunately, my experience with spam proxies is that they seem
to find MX records just fine. in fact, i have some anecdotal evidence
that, given multiple MX records, some spam proxies choose the _lowest_
priority one deliberately: we've seen many spam runs send to MX hosts
when the 'real' destination was available and answering.

in addition, we have had a number of complaints over the years from
remote sites that cannot send mail to addresses that don't have MX
records. this represents broken software, but it's not necessarily
easy to convince irate folks of that.

IMHO, the bottom line is that going MX-less is unlikely to have a
significant effect on spam volume (use the spamhaus blocklist if you
want a noticeable effect) and will result in some number of complaints
from 'real' folks who can't send you mail because they have busted software.

rp

rick pim                                           rick at post.queensu.ca
information technology services                          (613) 533-2242
queen's university, kingston   
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