Use of MX Records

[Barry Margolin]

In article <946tgg$75u at pub3.rc.vix.com>,
Smith, William E., Jr. <Bill.Smith at jhuapl.edu> wrote:
>
>According to O'Reilly's 3rd Edition DNS & BIND book each host should hae at
>least one MX record.  Furthermore, it suggests adding an MX record pointing
>to itself.  Should this be the case for all hosts, even say a Windows box
>which has no mail server, etc running on it.  Right now, we have 3 MX's
>generated for each host.  Itself, and our two main mail servers.  Some here
>have expressed concern over the use of MX records for workstations that
>really don't need them since they aren't having mail delivered directly to
>their box.  Just wondering if it's really necessary/optimal to add an MX for
>each host, even though they may not really need it.  Insight would be
>appreciated.

MX records are only necessary for hostnames that are expected to appear in
email addresses.  If you never send mail to user at something, no one will
ever try to look up the MX record of "something", so there's no need to
have one.

And if a machine doesn't run a mail server, you should never have an MX
record that points to it.

-- 
Barry Margolin, barmar at genuity.net
Genuity, Burlington, MA
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