Just started at a new company and one my first assignments is to look for alternatives to their inhouse monitoring system.
Their current solution is a .Net application that checks various devices over the WAN (since they are an IT-consulting firm that provides 24/7 support/"maintenance"). Devices range from routers/switches/printers to MS servers and services.
After reading countless posts on the site and googling extensively it seems the consensus is that some sort of Nagios/Munin mix is the way to go.
Which brings me to my question(s):
A) Is it possible to have a Nagios server running locally at the company and monitor various external sites over WAN? (They dont want a local Nagios server on each site as most sites are relatively small (10-25 hosts) and the number of sites is quite large (75-100)).
B) If so how would the agents contact the Nagios backend ? Through SSH? HTTP?
C) Aside from the fact that it would be susceptible for WAN-link failures, what would the immediate drawbacks of such a solution be?
Any feedback is appreciated, and I apologize in advance for any misconceptions as im quite new to the industry.