Clear a BIND nameserver's cache

For BIND 9.2.0 and earlier:

rndc flush

For earlier versions:

rndc restart

Determine DNS version

To verify the version of DNS running in server_name, execute:

dig @server_name version.bind chaos txt

Force an immediate refresh of a zone in a slave server

For BIND 9 and later:

rndc refresh <domain_name>

For earlier versions:

ndc reload <domain_name>