Is there a gnome applet that will let me configure a list of URLs to be verified and report when some is unavailable ? Preferably using notifiations.
The validation must use HTTP GET or HEAD .
Maybe you can take this as a base (needs python-appindicator and python-notify):
You could write a small bash script to throw notifications at you... Something like:
Your list of sites to check lives in
Then you just need to cron that up to run. You might need to export
Note that if you use a DNS intermediary like OpenDNS, if a domain name you ping doesn't exist, it'll hit their no-domain search server. Therefore it's probably safer (though less informative) to use IPs.
However, I suspect that since you said "URL" you might be looking at something that does a GET to the websites, reporting if it doesn't get a response? Can you clarify if a simple ping is enough? Some websites, for example, won't let you ping them. Worse, getting a ping doesn't guarantee that the website is actually up.
Since you've specified that you'd like this solution to be URL-based, you can use Oli's solution above, but first :
sudo apt-get install httping
And the script becomes :
NOTE : This wasn't working for me until I realised that I had configured my home router to use OpenDNS. This means that timed-out sites are redirected to the OpenDNS landing page instead, meaning that this script never generated an on-screen notification! One to watch.