nsupdate for dynamic DNS TSIG Updates
To update a DNS server dynamically using TSIG for authorization, run
nsupdate by doing the following:
$ nsupdate -d > server update.dyndns.com > zone $ZONE > key $KEY_NAME $KEY_HMAC > update add $HOST.$ZONE 60 A 10.0.0.1 > send > quit
For dynamic DNS hosts, $ZONE should be the third level DNS name like
But it doesn't explain what $HOST is expected to be?