[CentOS] DNS wizard

[Sam Drinkard]

John Hinton wrote:

> 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

What would really be neat, as well as useful, would be to take a live 
domain (I've effectually published mine) set everything in it proper, 
with full explainations, much in the way the dns how-to tried to do from 
prior Linux how-to days. Even tho this list is archived, I'd bet there 
could be some place where sample working configuration files could be 
placed for public access.  Better to see and read than experiment and 
still not know what one is doing. 

Just like me trying to remember all the stuff I needed to do to have a 
working xterm from remote, and getting into .xdefaults, X.resources, 
etc... when you don't use stuff all the time, you tend to forget the 
minor, but sometimes disasterous consequences.  It's not fun getting old 
and forgetting things, trust me!


-- 
Snowman