DNS Tool

Author: Andrew Keating <[email protected]>
April 19, 2012

This application measures DNS latency for the top 10 Alexa domains periodically 
and stores the time series and per-domain statistics in a MySQL database. It is 
useful for monitoring the performance of a DNS resolver over time.

To build, execute make
To run, execute ./dnstool delay

Delay is in seconds.

Building requires MySQL headers to be present in the include path. By default, 
these are assumed to reside in /usr/include/mysql. Edit the makefile if you 
need to modify this path.

Database information is configured through the file db.conf with keys 
(host, db, user, pass), one per line, separated by =

In order to avoid hitting DNS caches, random 8-character prefixes are prepended 
to each domain name (e.g., fdx53geb.google.com)

The program uses two DB tables, time_series and domain_stats. If the tables
do not exist in the database on execution, they are created automatically.

If some rows are already in the tables from a previous execution, it's no 
problem - we simply "catch up" the running variance from the time_series table.

If a DNS query times out, it is simply ignored - no rows are entered into
the database for it.

Tested on Ubuntu 10.04 LTS with LDNS 1.6.12, MySQL++ 3.1.0 and libmysqlclient 16

Some features which will be implemented in the future:
- Support for evaluating multiple DNS resolvers simultaneously - at the moment, 
it simply pulls the DNS resolver from /etc/resolv.conf
- Ability to configure domains from an input file, rather than a hard-coded 
string
- Concurrent queries
- Automated plot generation of time series values