Found this link that worked perfectly: https://www.andreagrandi.it/2014/09/02/configuring-ddclient-to-update-your-dynamic-dns-at-noip-com/
noip.com is one of the few dynamic DNS free
services that are reliable to use. If you have, like in my situation,
a Raspberry Pi connected to your home DSL and you want it to be always
reachable without knowing the current IP address (the IP could change
if you have a normal DSL service at home), you need a dynamic DNS
service.
To update the noip.com one you just need ddclient, a tool that is
available in Raspbian/Debian repository. You can install it with this
command:
sudo apt-get install ddclient
then you just need to edit /etc/ddclient.conf
protocol=dyndns2
ssl=yes
use=web, web=checkip.dyndns.com/, web-skip='Current IP Address: '
server=dynupdate.no-ip.com
login=yourusername
password=yourpassword
yourhostname.no-ip.org
and restart the client:
sudo /etc/init.d/ddclient restart
Please remember that noip.com free accounts have a limitation: they
need to be confirmed every 30 days (You will receive an email and you
need to click on the link contained to update your DNS).
Thanks to @NickSillito for the ddclient tip.