Thomas Kinnen ( )
Sat, 7 Feb 1998 18:06:06 -0500 (EST)

On Sat, 7 Feb 1998, Michael Whisenant wrote:

> this term loose as many people managing DNS have no clue) to set up a zone
> file incorrect. One such instance is when a person points an MX record to
> a CNAME entry.

That's not an DNS issue but a mailer issue. I just went back and checked
the DNS and Bind manual by O'Riley and you are allowed to CNAME MX records
but it is not recomended as some mailers do not resolve CNAME entries (pg
92.) This will can case a mail loop where a mailer will send mail to it's
alias and loop the mail to itself. Shows up a lot when there are
miss-configured Cw and DM macros in Sendmail.

>Or CNAME entries to CNAME entries in other zones. According
> to the protocol, and RFC this is not supposed to occur and while the end

Hmm, The only reference to this I could find was that there is a limit of
8 CNAMES in a chain to prevent CNAME looping. The example they give is of
a CNAME from out side the domain pointing to a CNAME within a domain (pg
314.) They also give an example of this on the next page.

As for MS DNS issues I could not find the KB article I was looking for but
did find was Q151416 that talks about one resource record per message and
compressed resoure records. The one I was looking for was the one that
talks about when MS's defaults to compressed even though the other DNS
server can not.

Thomas Kinnen
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