Why can I access to port 8080 only from localhost on Ubuntu?

To achieve the previous post, I had some problems today to access to my tomcat server from another machine. Ping OK but telnet 8080 KO... Humm, this smells firewall rules. Bingo! I didn't considered iptables as a firewall but it's one!

So, if you are in a secure network area, you can disable it temporarily with the following command :
sudo iptables -F
You can go further by reading this how-to page : https://help.ubuntu.com/community/IptablesHowTo