This is part of a series on diagnosing your website outage issues. This is part four; links to the other parts are here.
In Part 1 of this series we covered the overview of what could have broken to cause your website to go down. In Part 2, we started working through those possible issues by diagnosing DNS issues. In Part 3 we diagnosed routing issues. Now that we know your domain’s DNS is good, the routes are good, we’re going to start looking at any layers you may have in your architecture.
The term “layers’ refers to things like firewalls or Content Distribution Networks (CDN) that may be present in your architecture. If you don’t use these things, you can skip to the next section which I will link to here when it is ready.
A typical website architecture looks like this:
website visitor -> web hosting server
There are no layers involved in this architecture. Your visitor simply hits your website directly. That works just fine and represents probably 80% of the use cases out there, but an increasing number of website owners are starting to employ firewalls and CDNs to secure and speed up their sites. If you employ a firewall such as The Mighty Sucuri CloudProxy, your architecture changes to look like this:
website visitor -> Sucuri CloudProxy -> web hosting server
If you harken back to Part 2 where we discussed routing, then you will recognize that this change in architecture introduces another point of failure for your website. How do you test those parts to ensure they are functioning? There are a few options.