Frequently Asked Question
You can use netstat in a dos window to view a list of all ports being used by Microsoft Windows.
This command will list out all of the port in use and the ip address associated with it both locally and remote. At the same time it will give the associated PID or process id that the port is associated with. The PID can then be used to determine the program using the port.
This is done by opening the task manager and going to the details tab and looking for the file using the PID.
Displays protocol statistics and current TCP/IP network connections.
NETSTAT [-a] [-b] [-e] [-f] [-n] [-o] [-p proto] [-r] [-s] [-t] [-x] [-y] [interval]
-a Displays all connections and listening ports.
-b Displays the executable involved in creating each connection or listening port. In some cases well-known executables host multiple independent components, and in these cases the sequence of components involved in creating the connection or listening port is displayed. In this case the executable name is in  at the bottom, on top is the component it called and so forth until TCP/IP was reached. Note that this option can be time-consuming and will fail unless you have sufficient permissions.
-e Displays Ethernet statistics. This may be combined with the -s option.
-f Displays Fully Qualified Domain Names (FQDN) for foreign addresses.
-n Displays addresses and port numbers in numerical form.
-o Displays the owning process ID associated with each connection.
-p proto Shows connections for the protocol specified by proto; proto may be any of: TCP, UDP, TCPv6, or UDPv6. If used with the -s option to display per-protocol statistics, proto may be any of: IP, IPv6, ICMP, ICMPv6, TCP, TCPv6, UDP, or UDPv6.
-q Displays all connections, listening ports, and bound nonlistening TCP ports. Bound nonlistening ports may or may not be associated with an active connection.
-r Displays the routing table.
-s Displays per-protocol statistics. By default, statistics are shown for IP, IPv6, ICMP, ICMPv6, TCP, TCPv6, UDP, and UDPv6; the -p option may be used to specify a subset of the default.
-t Displays the current connection offload state.
-x Displays NetworkDirect connections, listeners, and shared
-y Displays the TCP connection template for all connections.
Cannot be combined with the other options. interval Redisplays selected statistics, pausing interval seconds between each display. Press CTRL+C to stop redisplaying
statistics. If omitted, netstat will print the current configuration information once.