Knowledge Base ISC Main Website Ask a Question/Contact ISC
Quick Jump Menu
Categories
There are no subcategories in this category.
11 How do I flush or delete incorrect records from my recursive server cache?

Sometimes a recursive server may have incorrect records in its cache. These may be as a result of an error made by a zone administrator, or as a result of a deliberately engineered cache poisoning attack. For cache problems relating to DNSSEC validation,…

12 Why does my authoritative-only nameserver try to query the root nameservers?

Check first that recursion really is disabled: recursion no; This will prevent your nameserver from performing iterative queries on behalf of any client queries that it receives, but it won't prevent your server from needing to make queries of its own in…

13 When does rndc reconfig flush the cache?

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…

14 How do I configure multiple views to share the same recursive cache?

The attach-cache option is used to configure cache-sharing between views. attach-cache cache_name; By default, each view has its own unique cache. When using the attach-cache option, you can specify a name for the cache that named creates for a view. If multiple…

15 Why does named log an error 'disabling RFC 1918 empty zones' when starting up?

In BIND 9.6-ESV-R5, 9.7.4, 9.8.1 (and newer versions of 9.6-ESV, 9.7 and 9.8 that supersede them), the warning message below may be encountered when named is starting: Warning: 'empty-zones-enable/disable-empty-zone' not set: disabling RFC 1918 empty zones…

16 Why are queries for some PTR records no longer forwarded since upgrading to BIND 9.9.0?

This behaviour may be encountered due to the introduction of automatic empty zones for RFC 1918 prefixes if you are using IP addresses within the RFC 1918 private address space. BIND provides a number of empty zones that are automatically configured and loaded…

17 What does named log message "deleted from unreachable cache" mean?

An example of the message being logged is: 02-Aug-2012 07:58:20.601 general: info: master 192.0.2.4#53 (source 192.0.2.8#0) deleted from unreachable cache BIND maintains a cache of unreachable masters to which it refers when handling a zone refresh. If a…

18 Why does rndc log warning key file ... exists, but using default configuration file (rndc.conf)?

After upgrading BIND to a current version, you might be surprised to see this warning when using rndc commands (although the command should still work as before, unless you've made other configuration changes): WARNING: key file (rndc.key) exists, but using…

19 Why does named log "error sending response"?

Sometimes on busy servers, named is unable to send a client response and will log messages similar to: client 192.0.2.17#4218: error sending response: unexpected error More recent versions of BIND have changed the error message slightly: client 192.0.2.123#48516…

20 Since upgrading to BIND 9.9 I'm seeing "maximum number of FD events (64) received"

Question: Since upgrading to BIND 9.9, I'm now seeing maximum number of FD events (64) received being logged frequently - why is this, and what should I do about it? Answer: An explanation of this logged message can be found in the article What does 'maximum…