Graded Lab: DNS

Introduction

In our last lab, DNS, we configured our environment with a full-blown DNS server on ns1 resulting in a bit of a "funny" environment. Hosts on the blue network, like s01, could resolve names for servers they could not reach and we had to provide a connection to the open internet for ns1. Today you will build a DNS deployment better tailored to the needs of our lab.

Design Requirements:



1. Hosts on the blue network should only have access to the blue network and not the open Internet
2. All of our hosts names (s01, w01,...) should be maintained by a single DNS Primary server
3. w01 needs to access the open internet and access to the internal name server
4. Use bind as our name server

Implementation Strategy:



1. Bind on s01:
   • Primary DNS Server for the domain example.com (s01 and w01 must be in the domain)
   • No caching behaviour (recursion)
   • No forwarding
2. Bind on w01:
   • Caching server
   • Slave/Secondary server for "example.com" with s01 as the master
   • /etc/resolv.conf must look like this

     nameserver localhost
     domain example.com 

Here is what we will build today

Prerequisites:

Before you start this lab you must have:

• The comp-10018 virtual lab appliance, comp-10018-vlab.ova found on the CSAIT lab systems.
• Oracle VirtualBox software, found on all lab systems at the college and available from http://virtualbox.org

Grading:

You will run the host_info_dns.sh script on s01 and w01, submitting the output files to Canvas. host_info_dns.zip

Hints:

You saw most of what you will need for this lab when you completed the first DNS lab. Here are a few hints to help you along...

1. Use the excellent tutorial from zytrax: DNS For Rocket Scientists
2. The s01 configuration is very similar to the configuration we built on ns1, except we do not allow recursion.
3. The w01 configuration is very similar to the configuration we built on ns1, except:
   
   
   • only listen on the loop-back interface
   • has a zone with type slave for example.com
   • limit the amount of memory we use for the DNS cache (w01 is a small system)