cname rr data lookup

[Kevin Darcy]

Yes, as long as the names that *cannot* be CNAMEs aren't CNAMEs.

If you have a lot of records, it might be worth it to script the 
generation of the CNAMEs rather than keying them all in.

                                                                        
                                                    - Kevin

Graham Turner wrote:

>Kevin, thanks for the mail back
>
>yes i did mean an A record
>
>so solution 1 seems a valid configuration - even if a little unwieldy given
>the rekey of alot of CNAME records ??
>
>GT
>
>"Kevin Darcy" <kcd at daimlerchrysler.com> wrote in message
>news:av5307$cfmk$1 at isrv4.isc.org...
>  
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>>Graham Turner wrote:
>>
>>    
>>
>>>as a migration step of hosts say olddomain.com to newdomain.com I am
>>>planning to provide a whole load of alias CNAME records in the zone file
>>>      
>>>
>for
>  
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>>>newdomain.com along the lines of
>>>
>>>host1.newdomain.com IN CNAME host2.olddomain.com
>>>
>>>this is to support the correct name resolution of a legacy host in
>>>olddomain.com in a transition phase from client whose resolver
>>>      
>>>
>configuration
>  
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>>>(and by implication its default devolution of unqualified names which is
>>>less preferable to modify) reflects newdomain.com
>>>
>>>for this to work the name in the data section of the CNAME RR must be
>>>resolvable using a host record.
>>>
>>>      
>>>
>>"Host record"? I assume you mean an A record.
>>
>>    
>>
>>>assuming this is a valid configuration what (if any) rules are there on
>>>      
>>>
>the
>  
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>>>name server being able to resolve this host record from say either;
>>>
>>>1. domain delegated to the legacy dns server(s)  hosting olddomain.com
>>>
>>>or
>>>
>>>2. do i have to make the dns server that is hosting newdomain.com
>>>authoritative for the olddomain.com by making it a secondary to the
>>>      
>>>
>legacy
>  
>
>>>dns server
>>>
>>>      
>>>
>>No, you're not forced to make either server slave anything from the
>>other server. However, there are some important rules about CNAMEs that
>>you need to be aware of:
>>
>>1) You can't point an MX record or an NS record at a CNAME. So your
>>delegation and MX targets (Internet SMTP mail server names) must still
>>be A records.
>>2) If a name owns a CNAME record, it cannot own any other records. The
>>most common gotcha associated with this rule is that the name of a zone
>>cannot own a CNAME (because then the SOA and NS records owned by the
>>name would violate the rule).
>>
>>
>>                                        - Kevin
>>
>>
>>
>>
>>    
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