5.1 Tools for DNS Debugging
After the configuration and startup of a name server, it is necessary to check whether the name server works correctly. Mistakes in DNS are very unpleasant. When a mistake in DNS occurs, applications sometimes do not start at all, but more often, the whole system seems to work very slowly. This applies especially to the configuration of a firewall. If the firewall has long response intervals, it is most likely due to an incorrectly functioning DNS.
There are some informative RFCs that focus on DNS problems. For example, RFC 1537 focuses on frequent mistakes in DNS and RFC 1713 focuses on tools for debugging.
There are two methods that can be used to check the configuration, which are as follows:
1. The first method is based on assuming the resolver’s role and sending DNS queries to your DNS server in the same way that the resolver does. In this case, you are testing whether the name server answers your queries as you expect it to. For such testing we will manage...
