[CentOS] DNS wizard

[John Hinton]

Les Mikesell wrote:

>On Thu, 2005-12-29 at 21:18, Sam Drinkard wrote:
>  
>
>>> 
>>>One other thing that might not be obvious: CNAMEs aren't
>>>just for the A record, they get all associated data too
>>>so you are providing an MX record for www.wa4phy.net
>>>and ftp.wa4phy.net.  It doesn't hurt anything but it
>>>might not be what you expect.
>>>
>>> 
>>>
>>>      
>>>
>>Not sure I follow what you are talking about Les.  Can you be a bit more 
>>specific?
>>    
>>
>
>Cnames are effectively the same as the record they
>point to.  You probably intend for any mail sent to
>user at wa4phy.net to be sent to the primary/secondary
>MX receivers you specified, but as a side effect
>of the CNAME, mail sent to user at www.wa4phy.net or
>user at ftp.wa4phy.net would go to the same places because
>the MX records also apply to them.  It isn't likely to
>matter in this case, but someday you might want to 
>direct mail to those addresses elsewhere and be surprised
>that you can't give them a different MX.  Or if you
>actually want mail to go to those addresses you might
>be surprised when they sometimes hit the secondary
>MX that might not be configured for them.
>
>  
>
I've almost never use CNAMES and really am wondering about a truly 
useful application. In this day of spam, it seems like less is best with 
regards to subdomains, such as the example above. CNAMES also require at 
least one extra loop in the lookup.. so why are they so widely used when 
an A record does the more defined and more limited task? There certainly 
seems to be some useful wizardry in CNAMEs, but darned if I can think of 
a use for basic web hosting types of situations.

Best,
John Hinton