OpenBSD DHCPD with Dynamic DNS September 25, 2012
Relatively simple setup to enable a local DHCP server with dynamic DNS updates for a lab domain.
Tested and implemented on OpenBSD 5.1.
bash-4.2# uname -a
OpenBSD puffy 5.1 GENERIC#160 i386
bash-4.2# cat /etc/myname
The shipped DHCPD server does not support ddns so we must install the ISC-DHCPD one.
bash-4.2# pkg_add -r ftp://mirror.esc7.net/pub/OpenBSD/5.1/packages/i386/isc-dhcp-server-22.214.171.124.tgz
You can verify that you installed it.
bash-4.2# pkg_info -a isc-dhcp-server-126.96.36.199 ISC DHCP Server
Create some additional NAMED files for logs.
bash-4.2# touch /var/named/named.run bash-4.2# touch /var/named/named_query.log bash-4.2# touch /var/named/named_dump.db bash-4.2# chown named:named /var/named/named.run bash-4.2# chown named:named /var/named/named_query.log bash-4.2# chown named:named /var/named/named_dump.db
You will want to change the permission since we are running as user NAMED.
bash-4.2# chown named:named /var/named/master bash-4.2# chgrp named /var/named/etc bash-4.2# chown named:named /var/named/etc/*
Ensure your permissions for /var/named/ are correct. The following are what mine look like.
you may not have some of the db. files just yet.
bash-4.2# ls -l /var/named/ drwxr-xr-x 2 root wheel 512 Jul 12 07:21 dev drwxr-x--- 2 root named 512 Jul 11 10:59 etc drwxrwxr-x 2 named named 512 Jul 13 06:26 master -rw-rw-r-- 1 named named 4564137 Jul 13 07:52 named.run -rw-rw-r-- 1 named named 0 Jul 12 07:31 named_dump.db -rw-rw-r-- 1 named named 0 Jul 12 07:31 named_query.log drwxrwxr-x 2 root named 512 Feb 12 10:32 slave drwxr-xr-x 2 root wheel 512 Jul 11 10:28 standard drwxrwxr-x 2 root named 512 Feb 12 10:32 tmp bash-4.2# ls -l /var/named/etc/ -rw-r----- 1 named named 1549 Jul 12 13:51 named.conf -rw-r----- 1 named named 77 Jul 11 10:59 rndc.key -rw-r--r-- 1 named named 3110 Feb 12 10:32 root.hint bash-4.2# ls -l /var/named/etc/master/ -rw-r--r-- 1 named named 794 Jul 13 06:26 db.10.120.10 -rw-r--r-- 1 named named 1478 Jul 13 06:26 db.lab.ttc
Edit your /etc/dhcpd.conf file. Use the one I've provided for reference/template.
Edit your /var/named/named.conf file. Use the one I've provided for reference/template.
Change the daemon in /etc/rc.d/dhcpd to point to /usr/local/sbin/dhcpd
I think this isn't the right way to do it since it may not stay during updates to the base os.
bash-4.2# sed -i 's/\/usr\/sbin\/dhcpd/\/usr\/local\/sbin\/dhcpd/' /etc/rc.d/dhcpd
Add both DHCPD and NAMED to your /etc/rc.conf.local file for startup.
bash-4.2# echo 'dhcpd_flags=""' >> /etc/rc.conf.local bash-4.2# echo 'named_flags="-u named -d 3"' >> /etc/rc.conf.local
Now start both daemons. Hopefully they start...
bash-4.2# /etc/rc.d/dhcpd start bash-4.2# /etc/rc.d/named start
I've noticed two machines in my lab that never got a ddns record set during DHCP addressing. Apparently not all systems play nice with DHCP and don't send their hostname when they communicate with the server. You can manually force this on a linux machine.
Fedora 11: echo 'send host-name "fred";' >> /etc/dhclient-eth0.conf Ubuntu 10.04: echo 'send host-name "barney";' >> /etc/dhcp3/dhclient.conf
Depending on distrobution and version you may have to look in different locations.
There may be cases were you are unable to send the hostname. You may force it within the dhcpd.conf file itself. Look at the dhcpd.conf file included for an example.
Questions/Comments/Priases can be sent to me at firstname.lastname@example.org