I suggest nagios and pingdom

Nagios is extremly flexible and very advanced. My Nagios system checks uptime, latency, ssh availability, http/s availability, and sends me an email if there is a problem. I am running Nagios in multiple environments with over 500 hosts. I have never had an issue with it. You can also use Cacti to graph the statistics of uptime/ latency, disk usage ...

I run nagios with over 20 servers, it is advanced, and monitors everything, cpu, disk, I/O, HTTPD, FTP, the lot, pings, anything, it is the best I have seen.

Cacti is also good.

I don't know why people are using pingdom and such services, not ideal really to monitor your own network as a business, they also can give false reports.

I agree, if you can't do it yourself, why bother? Nagios and Centreon are what I use, Centreon is just a web front end for nagios to give it steriods

For our Collocation clients we use Catci to monitor their servers bandwidth usage. http://www.cacti.net/ or http://www.cacti.net/features.php but I believe for the type of monitoring you're looking to do Nagios would be the way to go.

Correct, it costs less than what, £5 /mo to have a nice small VPS off site, which will most likely monitor 100+ servers, until you grow of course.

I will have a look at Centreon, sounds nice, we are in the middle of building a new tech panel into nagios, which fetches to do jobs and posts network issues inside WHMCS.

Cacti is nice, however, rrdtool seems to play games with the latest version for me.

Nagios can also be setup in a way to offer server monitoring to clients, for a fair price, it can be used as an addon service to clients using other servers elsewere.

Would go with nagios as well, pretty well established codebase so its very solid.

I use ManageEngine OpManager to monitor our servers. I have used it a lot in corporate IT so it was kind of a natural move for me.

They do have a nice free "professional trial" version that you can use to monitor up to 10 devices for free, or you can choose the 30 day trial and monitor unlimited for 30 Days.

For smaller companies with only a few devices the free professional is perfect.

Other than that my suggestions would either be Zenoss (community version) or Zabbix if you are looking to host something your self.

We like Pingdom. Pricing is nice, and their support is friendly.
I wish they would come out with an Android app soon, though.

For network and server services monitoring go for Nagios , the best ever tool for servers monitoring , for website monitoring you can go for siteuptime or pingdom

Yep we do the same setup though we add Pingdom on top mostly for the load time graphs and also the SMS if the site goes down, though I think there are also Nagios plugins that do the same thing.

We use a combination of PRTG and STrend to monitor and collect historical data on our network and servers. Is there specific information you want to collect or just get an over view of what's going on?

We were ready to implement Nagios to monitor our servers' response and performance, but then an experienced IT Professional suggested Pandora FMS (http://www.pandorafms.org/) instead.

He says it is easier and more flexible than Nagios.

Is anybody using Pandora FMS?
Can anybody comment on it?

Thanks,

Rodrigo