DNS help with mx records

[Barry Margolin]

In article <ac3j4c$61hb$1 at isrv4.isc.org>,
Ricardo Fitzgerald <axis at movinet.com.uy> wrote:
>my ermitagemontevideo.com zone is:
>
>$TTL 3D
>@		IN SOA	ns.ermitagemontevideo.com.	root.ermitagemontevideo.com. (
>			2002031806			; serial
>			8H				; refresh
>			2H				; retry
>			4W				; expiry
>			1 )				; minimum
>
>		NS	ns
>		MX	10 mail
>
>localhost	A	127.0.0.1
>
>
>gw		A	200.61.76.65
>
>
>ns		A	200.61.76.88
>		MX	10 mail
>
>www		CNAME	ns
>ftp		CNAME	ns
>
>mail		CNAME	ns  --> Here is where I´m not sure. mail is under the same
>IP, but I don't know if I have to write the record as a CNAME or this
>other way:
>
>mail            A       200.61.78.88
>                MX      10 mail
>
>Which is the correct way ? If I have mail and ns under the same ip
>200.61.76.88,
>should I configure mail as CNAME or as an A record as shown above ?

MX records are required to point to A records, not CNAME records.  So you
should either change all the MX records to point to "ns", or change the
record for mail to be an A record.

However, most mail implementations are pretty tolerant of this common
mistake.  If you're having problems, there's probably something else wrong
as well.

>Another question: linux is the gateway to the internal network, this
>computer

You didn't finish this question.

>-----------------------------------------------------------------------
>
>my 200.61.76 zone:
>
>$TTL 3D
>@	IN SOA	ns.ermitagemontevideo.com.	root.ermitagemontevideo.com.	(
>		2002031806			; serial
>		8H				; refresh
>		2H				; retry
>		4W				; expiry
>		1D	)			; minimum
>
>	NS	ns.ermitagemontevideo.com.
>
>65	PTR	gw.ermitagemontevideo.com.
>88	PTR	ns.ermitagemontevideo.com.
>88	PTR	mail.ermitagemontevideo.com. <---- I'm not sure about this!

If "mail" is a CNAME record then it shouldn't appear in a PTR record.  If
you use two A records, it's OK to have two PTR records, but you don't
usually need both of them, and they can cause confusion.

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