key.dns_resolver man page
key.dns_resolver — upcall for request-key to handle dns_resolver keys
/sbin/key.dns_resolver -D [-v] [-v] <keydesc> <calloutinfo>
This program is invoked by request-key on behalf of the kernel when kernel services (such as NFS, CIFS and AFS) want to perform a hostname lookup and the kernel does not have the key cached. It is not ordinarily intended to be called directly.
It can be called in debugging mode to test its functionality by passing a -D flag on the command line. For this to work, the key description and the callout information must be supplied. Verbosity can be increased by supplying one or more -v flags.
All errors will be logged to the syslog.
request-key.conf(5), keyrings(7), request-key(8)