Scan For Open Ports
Theres a very good scanner built into linux called nmap that will scan your system and display a report on any ports and if they are TCP and/or UDP.
Scan Your System For Open Ports
Do A SYN Port Scan
Any ports that show up you can cross check what the typical usage on the ports and services listing
This scan does a local system scan, ideally you need to scan your system from another machine and change "localhost" to your computers ip address. If you dont have another machine to use to scan your system you can use several free online scanners: