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dsc is a system for collecting and presenting statistics from busy DNS servers.
The dsc tool is written by Duane Wessels and maintained at the Measurement Factory (http://dns.measurement-factory.com/tools/dsc/). For more information also visit the DNS-OARC DNS page.
The dsc tool uses a CGI script to display data in a web browser. The interface allows user to change time scales, to select particular nodes within a DNS server cluster, and to isolate individual dataset keys.
dsc consists of the following components:
- A data collector
- A data presenter, where data is archived and rendered
- A method for securely transferring data from the collector to the presenter
- Utilities and scripts that parse XML and archive files from the collector
- Utilities and scripts that generate graphs and HTML pages
The detailed DSC manual is available in PDF format.
Collector
dsc has two major components: the Collector and the Presenter. The Collector process uses libpcap to recieve DNS messages sent and received on a network interface. It may run on the same machine as the DNS server, or on another system connected to a switch configured with port mirroring. A configuration file defines some number of datasets and other options. Datasets are dumped to disk every 60 seconds as XML files. A cron job copies the XML files to a separate server for archiving and further processing.
Presenter
The second component of dsc is called the Presenter. This component receives XML datasets from collectors. Since parsing XML files is slower than we'd like, an extractor process converts them to another format. Currently that format is a line-based text file, although we may use a relational database in the future.