there is one, but it doesn't seem to be documented.

echo refresh >/net/dns
# or you can escalate to
echo restart >/net/dns
# but then you might need to remount in some name spaces

On 24 January 2012 10:04, Henning Schild <henning@plan9.bell-labs.com> wrote:
I guess
dns should provide a ctl file to allow reconfiguration at runtime.