I believe that some people mentioned using a CNAME because they have used a 
CNAME in the past not knowing that they should not.  Many mail servers will 
send mail to mail servers with MX records pointed to a CNAME, but the ones 
that follow the guidelines will not.  The CNAME record is only a 
redirection record to another record.

Gilbert

At 10:01 AM 1/30/2002 -0700, you wrote:
>Gilbert T. Gutierrez, Jr. wrote:
>
>>The lookup name does not matter on the IP address as long as there is 
>>one.  I would point the MX record to "cpe-24-221-41-162.az.sprintbbd.net" 
>>not a CNAME record.
>>For Example:
>>ecloud.org NS ns1.hn.org
>>ecloud.org NS aux1.hn.org
>>www.ecloud.org CNAME ecloud.org
>>ecloud.org MX cpe-24-221-41-162.az.sprintbbd.net 10
>>ecloud.org A 24.221.41.162
>>Many mail servers will not accept mail unless it has a reverse lookup 
>>record associated with it.  Some mail servers will not send mail to 
>>servers that are referenced by a CNAME (The reverse lookup must match the 
>>MX record statement).
>
>cpe-blah-blah.net is the reverse dns lookup for 24.221.41.162 which is on 
>the router/firewall WAN side of the box.  The router forwards ports 25/110 
>if I ask it to.  So what I was asking was if mail sent to 
>CoolGuy@cpe-blah-blah.net goes directly to MX 10 linux.bogus.  inside the 
>LAN, transparently.
>
>By asking about aliasing that cpe- name, i was basically asking a stupid 
>question.  mail sent to an "alias" that is not registered domainname of 
>course will not even reach the machine.  That is one of those questions 
>you might ask after midnight.
>
>A lot of people mentioned using CNAME...which is what I was asking the 
>question for.  The sendmail tutorial on sendmail.org said that you cannot 
>use a CNAME, so...??  why do they say that?
>
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