Experience with DDNS (RFC 2136)

Chris Thompson cet1 at cam.ac.uk
Tue Oct 11 12:57:38 UTC 2011

On Oct 7 2011, Phil Mayers wrote:

>On 10/07/2011 06:43 PM, JINMEI Tatuya / 神明達哉 wrote:
>> Maybe an off topic in this thread, but out of curiosity, is there any
>> specific reason you don't use the database as the direct source of the
>> zone with BIND 9's dlz or PowerDNS?  In general it will be slower, and
>I can't speak for Chris but here, we rejected DLZ and similar because:
>  1. DNSSEC
>  2. Speed
>  3. Impedance mismatch between database schema and DNS
>  4. Perceived second-class status of DLZ
>  5. Loss of various things that are automatic if using zones (IXFR)
>  6. Too-tight coupling between the SQL DB and DNS

I think that more or less covers it for us as well, although I might add

 7. Poor documentation

Maybe that counts as 4b.

>Of all of them, #1 and #6 were probably the most important. Using a 
>decent programming language to map your SQL into DNS means you get 
>arbitrary flexibility. Having to shoehorn it into a small set of SQL 
>queries denies you that.

Our external database was designed by Tony Stoneley back in 2001-2002,
so DLZ would have looked even less like a possible solution back then.

I have kept an eye on DLZ developments over the years, and thought quite
seriously about using it for the re-implementation of the hidden master
for our "managed zone service" (for vanity domains, although that's not
how we describe them to the punters), but even there it didn't work out,
primarily for Phil's reasons #5 and #6.

Chris Thompson
Email: cet1 at cam.ac.uk

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