While building web applications, it's often important to keep an eye on the other services running on your server. Having access to the current status of public servers can empower your applications to make decisions and respond to problems automatically. Acknowledging a service is offline can also save endless support emails. In this tutorial, I'll show you how to keep track of your server status by scanning ports on your server with PHP.

Their example makes a socket connection to the remote port to see if there's a valid hookup. The wrap this inside a loop for ports 1 through 1000 to see what ports are open and responding on your local machine (doing this on a remote machine is just asking for trouble).

Their full example defines some of the common ports in an array and loops to check on their status. It sets out a base you can build on top of with things like their suggestions - logging scan results, repoting downtime and running a service-specific task.

Let's imagine that you want to build a page that will display snapshots of your latest work. [...] In such instances, the best solution is to make PHP scan your "portfolio" folder and dynamically create the code for you. If you want to update your page with a new snapshot, all that you need to do is drag the image, and its respective thumbnail, into the appropriate folders - and PHP will do the rest. Let's build it now!

The screencast comes complete with the entire source and a link to a demo to show the end result.

Having access to the current status of public servers can empower your applications to make decisions and respond to problems automatically. Acknowledging a service is offline can also save endless support emails. In this tutorial, I'll show you how to keep track of your server status by scanning ports on your server with PHP.

They show how to check a remote instance (a socket open with a timeout) and how to run through a list of ports, looping from one to one-thousand and running an fsockopen on each. They make a sample script to show these two combined - a simple page that loops through the common protocols (HTTP, FTP, SSH, etc) and checks to see if the remote machine is running something on that port.

• JavaScript/HTML Portscanning and HTTP Auth
• Bruteforcing HTTP Auth in Firefox with JavaScript
• JavaScript Scanning and expose_php=On

While the first two are interesting, it's the last of these that most directly applies to PHP. He gives a simple "proof of concept" that checks to see if the embedded image is the correct "size" to be related to a webserver running PHP with the expose_php setting set to "on".

The idea of this project is quite simple, I was thinking that offering this service to anyone who requests it could be a very nice idea. Offering to run the scan is the only way I could ensure that people are not using this scanner against any website.

Basically, his idea is to offer this service free of charge, but still restrict it to avoid malicious use. It would involve validation via an md5 hash to ensure that the website has been authorized to run it. Check out the blog entry for more details on how the scan would be run.