Knowledge Base ISC Main Website Ask a Question/Contact ISC
What is dyndb and how is it better than DLZ?
Author: Brian Conry Reference Number: AA-01420 Views: 614 Created: 2016-09-07 14:00 Last Updated: 2016-10-04 15:32 0 Rating/ Voters
Question:

What is dyndb?

Answer:

dyndb is a new plug-in interface for BIND for custom zone data providers.


Question:

Isn't there already DLZ for that?  Why should I port my provider from DLZ to dyndb?

Answer:

While both DLZ and dyndb allow for custom zone data providers, and are (or at least can be since 9.8) linked into BIND as shared libraries loaded at runtime, that's about as far as the similarities go.

First, the DLZ API was designed with the assumption that all of the data providers would be databases, therefore all of the data is passed through the API in text format to make it easier to use in SQL.  This requires translating the question into text format before the DLZ call and then translating the answer out of text format in order to build the response to send to the client.  This makes it pretty impossible to create a highly performant DLZ provider.

The dyndb API, on the other hand, is designed so that the custom provider connects into BIND using the same function interfaces that we use for our own internal databases, meaning that the API itself consumes the query data as it already exists within memory and doesn't impose any additional data translation.  Similarly, the data returned by the dyndb API is already in the proper format for use in building the reply to the client (or for other internal use, as appropriate).  Clearly this primarily benefits data providers that can work with those data structures directly rather than having to translate things to and from text.

Second, the dyndb API includes additional setup calls when BIND is configuring itself.  This allows the dyndb provider to, for example, pre-query the database for records and create a local in-memory cache of the data.  If used properly this can significantly improve performance immediately after starting BIND or configuring a new dyndb zone.

Finally, the limitations of the DLZ API prevented it from properly providing DNSSEC signed data, while the dyndb API has no such limitations.

The dyndb API was developed by Red Hat for the FreeIPA project and has been contributed by them for inclusion in BIND.

Thanks in particular to Adam Tkac and Petr Spacek of Red Hat for their contribution.



© 2001-2016 Internet Systems Consortium

Please help us to improve the content of our knowledge base by letting us know below how we can improve this article.

If you have a technical question or problem on which you'd like help, please don't submit it here as article feedback.

For assistance with problems and questions for which you have not been able to find an answer in our Knowledge Base, we recommend searching our community mailing list archives and/or posting your question there (you will need to register there first for your posts to be accepted). The bind-users and the dhcp-users lists particularly have a long-standing and active membership.

ISC relies on the financial support of the community to fund the development of its open source software products. If you would like to support future product evolution and maintenance as well having peace of mind knowing that our team of experts are poised to provide you with individual technical assistance whenever you call upon them, then please consider our Professional Subscription Support services - details can be found on our main website.

Feedback
  • There is no feedback for this article
Info Submit Feedback on this Article
Nickname: Your Email: Subject: Comment:
Enter the code below:
Quick Jump Menu