Perhaps one of the more important aspects to setting up a monitoring solution is knowing where to monitor from.
SaaS (Software as a Service) vendors that monitor from PoP (Points of Presence) around the world, offer a way to analyze performance from those locations. This type of monitoring can be useful for websites that only have an outwardly facing website, e.g. a storefront, blog, etc. However, this is not always beneficial for large corporations or organizations that have both internal and external websites that need monitoring for constant uptime.
Intranet applications are often kept within the corporate network and are not visible to the outside world; and, to monitor Intranet applications, it is essential to install software on a computer inside the network. External facing websites may also be located at the same company; but, is it a good idea to monitor them with the same computer that is monitoring the Intranet? Yes and no.
It is always good to monitor external facing websites from an internal location. My suggestion is to compliment this monitoring by setting up a second comptuer for monitoring outside the network or on a different network.
The benefit of this type of setup is the ability to have a fail-over monitoring and response time results for comparison. If a web application is slow for users outside the network, but not for internal users, then one can easily guess that the failure point is somewhere in between. It’s just logical deduction at that point.