Configure DHCP for Dynamic DNS CentOS 6

Configure DHCP for Dynamic DNS CentOS 6

At this point we have setup a Dynamic DNS Master Server, and a Dynamic DNS Slave server, but now since we have this configured for Internal DNS, we can also configure DHCP to dynamically add/update addresses to DNS, this is especially handy for new devices, kickstarts, etc.

At this point, as mentioned we are assuming the following:

You have a DDNS Master, if not, click here

You have a Linux DHCP Server, if not, click here

login, and su to root

add the following lines to /etc/dhcp/dhcpd.conf, you can get the rndc secret key from /etc/rndc.key

######################################
# — Allow Dynamic Updates to DNS — #
######################################
        ddns-update-style interim;
        deny client-updates;
        update-static-leases on;
        ddns-domainname “test.local”;

key rndc-key {
        algorithm hmac-md5;
        secret “some-key-ends-in==”;
}

zone test.local {
        primary master-server-ip;
        key rndc-key;
}

zone 1.168.192.in-addr.arpa. {
        primary 127.0.0.1;
        key rndc-key;
}

restart DHCP

service dhcpd restart

Fixed Addresses/Reservations:

if you have fixed addresses, you have to add the ddns-hostname parameter, otherwise it will update DNS with the improper forward/reverse DNS names, make sure to set this.

# — Specify DHCP Reservations/Fixed Addresses — #

        host somehost.test.local {
        hardware ethernet 00:24:b7:d8:9g:e0;
        fixed-address 192.168.1.103;
        ddns-hostname “somehost”;
        }

restart DHCP to verify the new parameters are correct

That’s it!

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