Should I bother with Network Monitoring Software?
There really is no quick answer to this question. For some people the answer is Yes. Because you never know if your server is offline when you are away from the computer. However for most Spark Rack customers, the answer is No. And we’ll explain why in a moment, but first…what is Network Monitoring Software?
Network Monitoring Software is a web service, or computer application that monitors the connection of a website, IP address or service located on a remote (outside your local computer) connection for downtime, and alerts you when it happens.
The problem with that is that most hosting companies, including Spark Rack, have firewalls and brute force detection software (anti-hacking) setup to prevent hacking. If you set your refresh interval (how often it refreshes the data) to something like 10 seconds, then every 10 seconds it will attempt to connect to the resource and report back.
But here in lies the problem: For example, lets say you have a hosting account with Spark Rack and you are on Server A, then you sign up for a free monitoring service, in this case we’ll say StatusCake.com. Now StatusCake and sites like it use what’s called “pinging” (Ping is a basic Internet program that allows a user to verify that a particular IP address exists and can accept requests) to detect whether Server A is reachable or not, but not all servers accept ping requests. Most shared hosting servers actually block ping requests, and block traffic on all unused service ports (a service port is a port a piece of software runs on, eg HTTP [web servers] use port 80). But again, if the monitor is querying requests too often, or repeats the request when it’s failed, the server will eventually block all requests from that IP address, making it appear as if that server is permanently offline. Even though it’s not.
Now, not all monitoring sites use pinging, some use CURL. CURL is a Unix function (recently adapted for use on Windows systems as well) that allows you to get information from URL’s. It stands for Client URL Request Library. You may already use CURL with some of your website files, images, etc. So it may be familiar. However CURL is also not as dependable as you may think. CURL uses DNS (Domain Name Service) to resolve or lookup a domain, page, or website and then report back the results. If there is a DNS problem, but your server is still online, CURL will not resolve and tell you your website is offline. But it is advised not to use providers who utilize pinging or CURL.
And that’s why we developed a system for our network that uses an externally connected, but internal out-of-band network (not accessible from outside our data centers, only accessible externally via the network center). This allows us to install software on all of our servers that reports back to the main systems every few seconds. So, if the software monitor on Server A notices that FTP is starting to slow down, or is shutting down FTP to all connections, it immediately notifies our administrators, while simultaneously adding a new open issue to our network center.
In the past, our administrators have had to manually approve new outages or issues before they were visible in the network center. Our new network center is completely automated.
