Squid is the most diffused caching proxy for the Web. Squid supports HTTP, HTTPS, FTP, and many more protocols. This proxy software reduces a lot of the bandwidth required to serve its clients and improves the response time, implementing a very good caching system. For all those reasons, it is quite evident why you should have Squid to monitor inside your network.
There are two primary ways to acquire data and metrics from Squid:
Using SNMP
Using
squidclient
If you're curious about the SNMP setup on the Squid server, you can have a look at the official documentation, in particular the section available at http://wiki.squid-cache.org/Features/Snmp.
We should avoid enabling SNMP on our Squid as it has been affected in the past by many overflows and issues. The last security issue, at the time of writing this, caused by SNMP enabled on Squid, is available at http://www.squid-cache.org/Advisories/SQUID-2014_3.txt, and as you can see, it is a really recent issue.
Fortunately, the...