DNS name compression with BIND9

[Kevin Darcy]

Mark Andrews wrote:
>> pascalpoirier at gmail.com wrote:
>>
>>     
>>> Hi there,
>>>
>>> I am working on a testsuite for DNS server. I would like to know if
>>> there is something to do to remove the name compression used by BIND9.
>>>
>>>       
>> Just stick to using names that have nothing in common with each other, 
>> so that label compression is not possible. For your (in)convenience 
>> there are plenty of TLDs from which to choose.
>>
>> Seriously, how valid can it be to test anything in DNS with 
>> label-compression disabled? Label compression is pervasive in day-to-day 
>> DNS. It would be like trying to do automotive crash-testing with 
>> vehicles that include no glass, rubber or plastic in their construction. 
>> Sure you could test like that, but would the results have any value?
>>
>>                                                                          
>>                                                    - Kevin
>>     
>
> 	It's useful if you want to test that the resolver can also
> 	handle uncompressed responses.  There is atleast one firewall
> 	that assumes that the first record in the answer section
> 	to a query will be a compression pointer to octet 12 of the
> 	reply.
>
> 	The is not true with DNAME.
>
> 	Being able to disable compression is a easy way to find
> 	implementation bugs like this.
>
> 	See lib/dns/compress.c / lib/dns/include/dns/compress.h for
> 	the code which handles compression.
>
>   
People are still writing new DNS resolvers from scratch? How many times 
does that wheel need to be re-invented?

                                                                         
   - Kevin