Knowledge Base ISC Main Website Ask a Question/Contact ISC
When does rndc reconfig flush the cache?
Author: ISC Support Reference Number: AA-00836 Views: 5774 Created: 2012-12-03 12:20 Last Updated: 2012-12-05 09:55 0 Rating/ Voters

Why does rndc reconfig flush the cache sometimes but not on other occasions?

Usually when issuing rndc reconfig to make changes to a running BIND 9 nameserver, you expect it to retain the current working cache of learned RRsets.

However, there are a few changes that you can make to the configuration that might be incompatible with what has already been cached - and in those circumstances, named will also start with a new and empty cache following the reconfig.  Here are the settings that, if changed, will result in rndc reconfig clearing cache:

  • check-names
  • zero-no-soa-ttl
  • max-cache-size
  • max-cache-ttl
  • max-ncache-ttl
  • dnssec-validation
  • dnssec-accept-expired

See also the limitations on views that share cache

The criteria for whether or not two (or more) views configured in a BIND nameserver may share cache are that the policy settings listed above are consistent between views.  The attach-cache option is used to configure cache-sharing.


© 2001-2017 Internet Systems Consortium

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
Quick Jump Menu