Exercice Smokeping-DNS
Install SmokePing
Choose one of your servers to install smokeping
apt-get install smokeping
sudo ln -s /etc/smokeping/apache2.conf /etc/apache2/sites-available/smokeping.conf
sudo a2ensite smokeping
Now navigate to:
http://hostXX.ws.wacren.net/cgi-bin/smokeping.cgi

... replacing XX with the number of the host you choose
Within a few minutes, data should appear on the graph.
Let's now add a DNS check!
Configure DNS check for your 3 NS
cd /etc/smokeping/config.d/
sudo editor Probes
At the end of the file, add:
+EchoPingDNS

binary = /usr/bin/echoping
offset = 50%

Save the file and exit, then:
sudo editor Targets
At the end of the file, add:
++ PrimaryAuth
menu = My Primary DNS
title = My Primary DNS
probe = EchoPingDNS
host = hostXX.ws.wacren.net
dns_request = yourdomain
dns_type = NS


++ SecondaryAuth
menu = My Secondary DNS
title = My Secondary DNS
probe = EchoPingDNS
host = hostYY.ws.wacren.net
dns_request = yourdomain
dns_type = NS


++ Cache
menu = My Cache DNS
title = My Cache DNS
probe = EchoPingDNS
host = hostZZ.ws.wacren.net
dns_request = www.google.com
dns_type = A

Save the file and exit, then:
sudo service smokeping restart

Now Configure DNS check for Google Public DNS
++GoogleCache
menu = Google DNS Cache
title = Google DNS Cache
probe = EchoPingDNS
host = google-public-dns-a.google.com.
dns_request = www.ucad.sn.
dns_type = A

Now Configure DNS check for A RootServer
++A RootServer
menu = A Root Server
title = A root Server
probe = EchoPingDNS
host = a.root-servers.net
dns_request = .
dns_type = SOA

Navigate back to http://hostXX.ws.wacren.net/cgi-bin/smokeping.cgi
... you will need to wait a few minutes (5-10) for data to appear.