The goal here is to monitor DNS servers running BIND version 9 and graph the various statistics that it records about itself. The statistics will be made available to the Net-SNMP daemon by a script. From there, the data can be polled by whatever NMS you choose to use.

Table of Contents

• Getting Stats from BIND
• Serving Stats via SNMP
• Download for BIND 9.4
• Download for BIND 9.6 and Newer
• Notes

The goal here is to monitor servers running Postfix to determine the number of email messages delivered locally and abroad and to graph that data. The data will be made available via Net-SNMP for collection using your NMS of choice.

• Postfix homepage: http://www.postfix.org/

Basis for this Work

The methods outlined below are based on the work of Craig Sanders http://taz.net.au/postfix/mrtg/. Some things that are done different here:

• Only one database file is used for storing the data instead of two.
• Instead of recording two sets of numbers (the current reading and the previous reading), subtracting them, and then returning the difference, the method below lets MRTG/Cacti/whatever you're using perform that operation itself (as they've been designed to). This simplifies the process a fair bit. [On a side note, the reason Craig's method still works is because he's using the gauge option in his mrtg.cfg file]
• The script that pulls the data out of the statistics database has been rewritten in C in order to eek out a bit more performance and reduce the overhead of feeding the data to Net-SNMP.

Code

update-mailstats.pl

Watches the Postfix maillog file and stores a tally of sent and received email in a small database. This script requires the File::Tail module from CPAN.

postfix-stats-get.c

Retrieves data out of the database file.

Compile postfix-stats-get.c and move it to /var/net-snmp.