pdns_recursor

# rec_control¶

## Synopsis¶

rec_control [OPTION]… COMMAND [COMMAND-OPTION]…

## Description¶

rec_control allows the operator to query and control a running instance of the PowerDNS Recursor.

rec_control talks to the recursor via a the ‘controlsocket’. Which is usually located in /var/run . The –socket-dir or the –config-dir and –config-name switches control to which process rec_control connects.

## Examples¶

To see if the Recursor is alive, run:

# rec_control ping


To stop the recursor by hand, run:

# rec_control quit


To dump the cache to disk, execute:

# rec_control dump-cache /tmp/the-cache


## Options¶

 --help provide this helpful message. --config-dir= Directory where the recursor.conf lives. --config-name= Name of the virtual configuration. --socket-dir= Where the controlsocket will live, please use –config-dir instead. --socket-pid= When running in SMP mode, pid of pdns_recursor to control. --timeout= Number of seconds to wait for the remote PowerDNS Recursor to respond. Set to 0 for infinite.

## Commands¶

Add a Negative Trust Anchor for DOMAIN, suffixed optionally with REASON.
Add a Trust Anchor for DOMAIN with DS record data DSRECORD. This adds the new Trust Anchor to the existing set of Trust Anchors for DOMAIN.
current-queries
Shows the currently active queries.
clear-nta DOMAIN
Remove Negative Trust Anchor for one or more DOMAINs. Set domain to ‘*’ to remove all NTA’s.
clear-ta [DOMAIN]…
Remove Trust Anchor for one or more DOMAINs. Note that removing the root trust anchor is not possible.
dump-cache FILENAME

Dumps the entire cache to FILENAME. This file should not exist already, PowerDNS will refuse to overwrite it. While dumping, the recursor will not answer questions.

Typical PowerDNS Recursors run multiple threads, therefore you’ll see duplicate, different entries for the same domains. The negative cache is also dumped to the same file. The per-thread positive and negative cache dumps are separated with an appropriate comment.

Note

pdns_recursor often runs in a chroot. You can retrieve the file using:

rec_control dump-cache /tmp/file
mv /proc/$(pidof pdns_recursor)/root/tmp/file /tmp/filename  dump-edns FILENAME Dumps the EDNS status to the filename mentioned. This file should not exist already, PowerDNS will refuse to overwrite it. While dumping, the recursor will not answer questions. Note pdns_recursor often runs in a chroot. You can retrieve the file using: rec_control dump-edns /tmp/file mv /proc/$(pidof pdns_recursor)/root/tmp/file /tmp/filename

dump-nsspeeds FILENAME

Dumps the nameserver speed statistics to the FILENAME mentioned. This file should not exist already, PowerDNS will refuse to overwrite it. While dumping, the recursor will not answer questions. Statistics are kept per thread, and the dumps end up in the same file.

Note

pdns_recursor often runs in a chroot. You can retrieve the file using:

rec_control dump-nsspeeds /tmp/file
mv /proc/$(pidof pdns_recursor)/root/tmp/file /tmp/filename  dump-rpz ZONE NAME FILE NAME Dumps the content of the RPZ zone named ZONE NAME to the FILENAME mentioned. This file should not exist already, PowerDNS will refuse to overwrite it otherwise. While dumping, the recursor will not answer questions. Note pdns_recursor often runs in a chroot. You can retrieve the file using: rec_control dump-rpz ZONE_NAME /tmp/file mv /proc/$(pidof pdns_recursor)/root/tmp/file /tmp/filename

dump-throttlemap FILENAME

Dump the contents of the throttle map to the FILENAME mentioned. This file should not exist already, PowerDNS will refuse to overwrite it otherwise. While dumping, the recursor will not answer questions.

Note

pdns_recursor often runs in a chroot. You can retrieve the file using:

rec_control dump-rpz ZONE_NAME /tmp/file
mv /proc/$(pidof pdns_recursor)/root/tmp/file /tmp/filename  get STATISTIC [STATISTIC]… Retrieve a statistic. For items that can be queried, see Metrics and Statistics get-all Retrieve all known statistics. get-ntas Get a list of the currently configured Negative Trust Anchors. get-tas Get a list of the currently configured Trust Anchors. get-parameter KEY [KEY]… Retrieves the specified configuration parameter(s). get-qtypelist Retrieves QType statistics. Queries from cache aren’t being counted yet. help Shows a list of supported commands understood by the running pdns_recursor ping Check if server is alive. quit Request shutdown of the recursor. quit-nicely Request nice shutdown of the recursor. reload-acls Reloads ACLs. reload-lua-script [FILENAME] (Re)loads Lua script FILENAME. If FILENAME is empty, attempt to reload the currently loaded script. This replaces the script currently loaded. reload-lua-config [FILENAME] (Re)loads Lua configuration FILENAME. If FILENAME is empty, attempt to reload the currently loaded file. Note that FILENAME will be fully executed, any settings changed at runtime that are not modified in this file, will still be active. Reloading RPZ, especially by AXFR, can take some time; during which the recursor will not answer questions. reload-zones Reload authoritative and forward zones. Retains current configuration in case of errors. set-carbon-server CARBON SERVER [CARBON OURNAME] Set the carbon-server setting to CARBON SERVER. If CARBON OURNAME is not empty, also set the carbon-ourname setting to CARBON OURNAME. set-dnssec-log-bogus SETTING Set dnssec-log-bogus setting to SETTING. Set to ‘on’ or ‘yes’ to log DNSSEC validation failures and to ‘no’ or ‘off’ to disable logging these failures. set-max-cache-entries NUM Change the maximum number of entries in the DNS cache. If reduced, the cache size will start shrinking to this number as part of the normal cache purging process, which might take a while. set-max-packetcache-entries NUM Change the maximum number of entries in the packet cache. If reduced, the cache size will start shrinking to this number as part of the normal cache purging process, which might take a while. set-minimum-ttl NUM Set minimum-ttl-override to NUM. top-queries Shows the top-20 queries. Statistics are over the last ‘stats-ringbuffer-entries’ queries. top-pub-queries Shows the top-20 queries grouped by public suffix list. Statistics are over the last ‘stats-ringbuffer-entries’ queries. top-largeanswer-remotes Shows the top-20 remote hosts causing large answers. Statistics are over the last ‘stats-ringbuffer-entries’ queries. top-remotes Shows the top-20 most active remote hosts. Statistics are over the last ‘stats-ringbuffer-entries’ queries. top-servfail-queries Shows the top-20 queries causing servfail responses. Statistics are over the last ‘stats-ringbuffer-entries’ queries. top-bogus-queries Shows the top-20 queries causing bogus responses. Statistics are over the last ‘stats-ringbuffer-entries’ queries. top-pub-servfail-queries Shows the top-20 queries causing servfail responses grouped by public suffix list. Statistics are over the last ‘stats-ringbuffer-entries’ queries. top-pub-bogus-queries Shows the top-20 queries causing bogus responses grouped by public suffix list. Statistics are over the last ‘stats-ringbuffer-entries’ queries. top-servfail-remotes Shows the top-20 most active remote hosts causing servfail responses. Statistics are over the last ‘stats-ringbuffer-entries’ queries. top-bogus-remotes Shows the top-20 most active remote hosts causing bogus responses. Statistics are over the last ‘stats-ringbuffer-entries’ queries. top-timeouts Shows the top-20 most active downstream timeout destinations. Statistics are over the last ‘stats-ringbuffer-entries’ queries. trace-regex REGEX Emit resolution trace for matching queries. Empty regex to disable trace. Queries matching this regular expression will generate voluminous tracing output. Be aware that matches from the packet cache will still not generate tracing. To unset the regex, pass trace-regex without a new regex. The regular expression is matched against domain queries terminated with a ‘.’. For example the regex ‘powerdns.com$’ will not match a query for ‘www.powerdns.com’, since the attempted match will be with ‘www.powerdns.com.’.

In addition, since this is a regular expression, to exclusively match queries for ‘www.powerdns.com’, one should escape the dots: ‘^www.powerdns.com.$’. Multiple matches can be chained with the ‘|’ operator. For example, to match all queries for Dutch (.nl) and German (.de) domain names, use: ‘.nl.$|.de.$’. unload-lua-script Unloads Lua script if one was loaded. version Report running version. wipe-cache DOMAIN [DOMAIN] […] Wipe entries for DOMAIN (exact name match) from the cache. This is useful if, for example, an important server has a new IP address, but the TTL has not yet expired. Multiple domain names can be passed. DOMAIN can be suffixed with a ‘$’. to delete the whole tree from the cache. i.e. ‘powerdns.com\$’ will remove all cached entries under and including the powerdns.com name.

Note: this command also wipes the negative cache.

Warning: Don’t just wipe “www.somedomain.com”, its NS records or CNAME target may still be undesired, so wipe “somedomain.com” as well.