Eliminating the "www" Portion of a URL
barmar at bbnplanet.com
Tue Mar 14 17:11:10 UTC 2000
In article <200003141653.KAA20332 at achilles.ctd.anl.gov>,
Barry Finkel <b19141 at achilles.ctd.anl.gov> wrote:
>>I imagine there are still some misguided mailers out there that use
>>the address record for a domain name instead of the MX records
>>to determine where to deliver the mail.
>Last week I worked on a mail problem with a Macintosh-based mailer.
>When it tried to send mail to
>and it did not find an MX record for the full name, it did NOT look for
>an "A" record; it then looked for an MX record for the sub-domain
That's the parent domain, not a sub-domain.
>and in our case, that MX record pointed to a different mail host than
>the "aaa" node, where the recipient's mailbox resides. Once I added
>an MX record for aaa that pointed to itself, mail from this Mac mailer
That mailer is totally broken. Nothing in the Internet standards suggests
this behavior, and they specifically say that the A record for
aaa.bbb.ccc.com should be used if there's no MX record. The MX record is
used as a way of redirecting mail away from the host; the "normal" action
is to send the mail to the host specified in the email address.
I could understand this behavior as a fallback if aaa doesn't have an MX
record or A record. However, if that's the behavior that the destination
site really wanted, they could easily have installed a wildcard MX record
(basically, the sending mailer would be pretending that the bbb.ccc.com MX
record is also a wildcard MX record).
Barry Margolin, barmar at bbnplanet.com
GTE Internetworking, Powered by BBN, Burlington, MA
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