Configuring and Managing MPE/iX Internet Services (MPE/iX 6.5)

Chapter 8 139
DNS BIND/iX
DNS BIND Troubleshooting Steps
DNS BIND Troubleshooting Steps
1. Resources: Find a resource who is experienced with DNS BIND/iX!
If you’re entering into this without DNS BIND/iX experience, you’re
off to a difficult start. Problems with this product are generally
caused by poor configuration, so it’s critical to have a DNS BIND
literate engineering resource available for problem classification and
management.
2. Check the Obvious: Those with experience in DNS BIND
troubleshooting will have built up a number of quick “sanity checks”
that they use. Often, these will result in a quick resolution without
having to progress onto the next stages. If you don’t have the
experience (and can’t find someone that does... recommended) or find
that you’re still unable to find the answer, you’ll need to progress to
the next steps.
3. Detailed Problem Description: Historical information is very
valuable... is this a new DNS BIND installation, or has the site
suddenly started to experience problems? No matter what the
history, you will need to find out and document the exact symptoms
being experienced.
It Used to Work: Find out if the DNS Administrator is aware of any
configuration or network topology changes that could be tied to the
recent DNS BIND problems. Make a note of anything they can
suggest. Generally, these problems are caused by an incorrect
configuration change, or some change in network topology, resulting
in lost connectivity to systems required by the DNS environment (no
route to a required system, an internal or external nameserver is
down, system name/IP address change, poor configuration, and so
forth.
New Configuration: In 99% of DNS BIND problems, the cause is
poor configuration. Unfortunately, DNS is not an easy service for the
novice to configure. There are many pitfalls waiting to trip a user. In
a new configuration situation, you’ll find the following steps will
probably be needed.
4. Topology Information: Obtain and document a detailed
description of the DNS topology used in this environment,
Information on all the involved systems will be needed. It’s
important to be able to picture how all the systems connect to one
another and the inter-dependencies any have with one another. If
possible, an ASCII diagram of the topology is very often worth the
effort (labeling each node with its system and DNS information, see
Figure 8-1).