For the last four years I’ve been using the DHCP and DNS server roles on my Microsoft 2003 R2 server to form a DDNS (Dynamic DNS) solution and it’s been working well. It’s a fairly simple setup where:<\/p>\n
No mystery what’s happening there. For the server in question, the roles had expanded to include being an AD master, WSUS server and web server for our intranet, again nothing too major for a small organisation. BUT… one of my constant gripes was the time it took the server to load after each restart. Some cursory research pointed to the fact that it was waiting for the DNS server to startup and that was causing some delays\/problems for the AD. To add to motivation, there was only one DNS server, which meant when it went down… NO DNS RESOLUTION!<\/p>\n
So the idea was born to recycle a few of the Pentium III Dell Optiplex’s we had gathering dust into a primary DNS servers, with a secondary slave. I didn’t want to load Windows Server onto these boxes because (A) They were too low spec, and (B) I didn’t want to breach licencing obligations.<\/p>\n
Ubuntu to the rescue.<\/p>\n
It’s no secret I like Ubuntu with its solid packages and extensive support, so the 32-bit version of the server software was perfect for what I wanted to do. The plan: Two boxes running BIND9 (the DNS service) and one running DHCP3-SERVER, with updates from “Master” to “Slave” and the same forward and reverse lookup zones I have with Windows.<\/p>\n
The specifications of your hardware are dependant on the size of your organisation and the ultimately the number of “requests” you expect to get. We’re only small and I only needed it to service resolution for the internal subnet so the PIII’s were going to be fine. I threw as much memory into the units as I could, but based on some of the reading it should be >= 320MB.<\/p>\n
The OS install was standard, with me defining a static IP address and configuring a SWAP size of 2x the amount of physical RAM. At the end of Ubuntu’s install you can select the DNS server as additional software to be installed but for this guide I’ll assume you didn’t.<\/p>\n
Once the install is finished it’s a good idea to check for any updates.<\/p>\n
sudo aptitude update\r\nsudo aptitude safe-upgrade<\/pre>\nPackages<\/h3>\n
First, we need BIND9<\/strong>, and I also include the dnsutils<\/strong> packages for testing and troubleshooting.<\/p>\n
sudo aptitude install bind9 dnsutils<\/pre>\nNext, the DHCP3 package.<\/p>\n
sudo aptitude install dhcp3-server<\/pre>\nPrimary Master<\/h2>\n
Overview<\/h3>\n
There a many ways to configure BIND9<\/strong>. Some of the most common configurations are a caching nameserver, primary master, and as a secondary master.<\/p>\n
When configured as a caching nameserver BIND9<\/strong> will find the answer to name queries and remember the answer when the domain is queried again.<\/p>\n
As a primary master server BIND9<\/strong> reads the data for a zone from a file on it’s host and is authoritative for that zone.<\/p>\n
In a secondary master configuration BIND9<\/strong> gets the zone data from another nameserver authoritative for the zone.<\/p>\n
Preliminary setup<\/h3>\n
The first thing we do is setup a few references and settings in BIND9’s conf file. Note: some lines may already be present in the file, so make sure you avoid duplicates.<\/p>\n
cd \/etc\/bind\r\nsudo vi named.conf\r\n\r\nacl \"trusted\" {<\/span>\r\n 1.2.3.0\/24<\/strong><\/em>;<\/span>\r\n localhost;<\/span>\r\n localnets;<\/span>\r\n};<\/span>\r\ncontrols {<\/span>\r\n inet 127.0.0.1 allow {127.0.0.1; 1.2.3.4<\/strong><\/em>; } keys { \"rndc-key\"; } ;<\/span>\r\n};<\/span>\r\ninclude \"\/etc\/bind\/named.conf.options\";<\/span>\r\ninclude \"\/etc\/bind\/named.conf.local\";<\/span>\r\ninclude \"\/etc\/bind\/named.conf.default-zones\";<\/span><\/pre>\n