crednsc − credns control script.


crednsc −c configfile start | stop | reload | rebuild | restart | running | update | notify | patch


Crednsc is the shell script that used to control credns(8) and zonec(8) from credns distribution. Crednsc is also suitable to be linked into /etc/rc.d directory on BSD like systems for automatic startup of credns(8) at boot time.

At every invokation, crednsc will try to read the credns.conf(5) configuration file. An example of such configuration file is distributed with the credns package as credns.conf.sample. The config file is checked for errors before it is used, see credns−checkconf(8).

Possible crednsc applications are:


Start credns(8).


Shut down credns(8) by sending SIGTERM to it.


Initiate credns(8) name space database reload by sending SIGHUP.


Rebuild the credns(8) database by invoking zonec(8) with appropriate arguments.


Restart crednsc(8). This equals to crednsc stop && crednsc start.


Check whether credns(8) is running. Returns error message and error code if it is not running, and no message and zero error code otherwise.


Updates all the slave zones which have allow−notify: from localhost ( or ::1) allowed. If a TSIG key is specified for the allow−notify statement in the config file, it will be used to secure the notify. Note that credns keeps track of zone timeouts automatically, this is only needed if you want to manually force updates by sending notify messages to the localhost.

Another method you can use is to stop credns, delete the xfrd.state file and then start credns again. It will try to update all zones. This method does not require allow−notify: statements.


Sends notify messages to all the slaves for all the zones that have the notify: keyword in the credns.conf file. If a TSIG key is specified for a notify statement, it will be used to secure the notification message to that slave server.


Merge zone transfer changes back to zone files. It reads in the credns database (credns.db) and difffile (ixfr.db), and overwrites the zone text files if they have been updated. Running this regularly ensures that the difffile does not grow infinitely. If any zone text files have been changed (including those of the master zones), the credns.db is rebuild and credns is reloaded.


−c configfile

Specify configfile to use instead of the default /etc/credns/credns.conf.



Configuration file for credns to change default pathnames and credns flags. The zone names, pathnames to zone files and access control lists are also in credns.conf(5).


default credns database


Lockfile for the credns database access by operator tools.


Journal of zone transfers, the diff file containing the new zone contents transferred.


State for the zone transfer process of credns. Contains timeouts for the zones and whether zones are expired.


the process id of the name server.


Crednsc will return zero return code if operation was successful and an error message to standard output plus a non−zero return code otherwise.


credns(8), credns.conf(5), credns−checkconf(8), credns−notify(8), credns−patch(8), credns−xfer(8)


Credns was written by NLnet Labs.

NSD was written by NLnet Labs and RIPE NCC joint team. Please see CREDITS file in the distribution for further details.


Syntax checking of the config file is rudimentary and error messages may be wrong. If you do a crednsc patch, whilst a (long) zone transfer is busy, the zone transfer contents will be partially lost. After a reload, this will be detected and the zone transfer should be restarted. The reload that happens at the end of crednsc patch also frees up memory churn in credns caused by zone transfers.


Wed Sep 25 2013

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