Simple bash script to monitor a webserver on different ports (here smtp, dns, http & https but it can be customized) I'm sure there is over 100 available programs doing this but I wanted something with small memory usage. Also, I only wanted to be notified once, notifications are receive by SMS on my cell. With the software I was using before, I was getting notified every minute until I could reach a computer and fix the problem or stop monitoring which was quite annoying.