I've used a modified version of the script for over a year now and was able to determine unreliable sites with it. Of course there can be temporary server issue

I've used a modified version of the script for over a year now and was able to determine unreliable sites with it. Of course there can be temporary server issues and when you try to access the site it works again. The script I wrote checks multiple sites in one go and sends one mail per script execution, if there are errors. I found that more manageable, the code for it is on GitHub https://github.com/yaph/sitemonitor https://github.com/yaph/sitemonitor