Check Open Ports on your Linux Computer
It is always a good idea to keep an open eye on ports listening on your computer. The easiest method to do that is to install Nmap ( sudo apt-get install nmap ), and run sudo nmap localhost soon after installation. That should tell you what ports are open out of the box. Run Nmap often and if you see a new entry in the list of open ports that you are not familiar with, try to access it from a browser ( localhost:XYZ, where XYZ is the port number). If that does not tell you anything useful, consult Wikipedia's List of TCP and UDP port numbers .