Configuring ISC DHCP to send DNS dynamic updates to BIND

This assumes you already have an ISC dhcp server setup, and you also
have ISC BIND 8 or 9.

This configuration works inside my firewall where I use a private
domain name - unixpeople.internal.

First, you will need to generate a key:
# dnssec-keygen -a HMAC-MD5 -b 128 -n HOST unixpeople.internal

This will generate two files similar to:
Kunixpeople.internal.+157+24837.key
Kunixpeople.internal.+157+24837.private

Cut the data from the "Key:" line in the *.private file and use that
as the secret key in the appropriate stanza below.

Add the following to your dhcpd.conf:
----
#ddns-update-style ad-hoc;
ddns-update-style interim;
ddns-domainname "unixpeople.internal";
ddns-rev-domainname "in-addr.arpa";
one-lease-per-client off;
# damn dhcp server doesn't send updates for static addresses, but
# apparently this will
update-static-leases on;

# AWB - added this key to allow secure dynamic update
key unixpeople.internal {
        algorithm hmac-md5;
	secret "xie9rtGqq3dmMPhEwNo7Hw==";
};
----

Edit the named.conf for bind and add the same key stanza AND add
the the key statement to all the zone statements that should
accept dynamic updates:

----
zone "unixpeople.internal" {
        allow-update {key unixpeople.internal;};
        type master;
        file "db.unixpeople.internal";
};

zone "37.168.192.in-addr.arpa" {
        /* allow-update { 192.168.37.2;};*/
        allow-update {key unixpeople.internal;};
        type master;
        file "db.192.168.37";
};

----

Now restart both BIND and DHCP and you should be fine.