For Windows and Linux use the - netstat -a command, for this Macintosh I use the whois connected widget.
open windows firewall click on exceptions tab click on edit check ports or click on advance tab sevices edit
By ports you could be referring to physical connection ports on a host machine, if so then all can be abused in some form to compromise or damage a machine. Physical access to a computer is often considered a 'game over' in terms of security. IF you mean TCP/UDP connection ports (network) then any open port can offer an attack surface. It is best practice to close all unused ports leaving open on those specifically needed. Using a firewall to do this is common practice, these can be in the form of software, embedded or dedicated hardware. Closing unused ports on edge devices (routers and servers) is a standard move when setting up a network. Be aware that any ports that are open can be subject to port redirection attacks, in this instance the use of a firewall and Access Control Lists (ACL's) can help mitigate this threat.
Look for an oblong shaped brick/card with fans on it that has many video ports on it.
You have to setup a router and open the ports in the router for this purpose. But Pacenet have blocked many ports so you can go to their local office and ask them to open the ports.
portcall
Open the ports in a computer depends on the platforms and operating system being used . Open the Windows Firewall by clicking the Start button and clicking on the Control Panel. On the left pane, there is the Advanced settings which will open the ports.
Ports are like doors to a computer each computer has many ports. Without any open ports your computer wouldn't be able to access the internet, to find open ports you can try a portscan
wiki
NoYou can open the computer up and remove the USB ports.
firewall
A website that shows how to open ports in a firewall is the Sever Fault website. Another website that shows how to open ports in a firewall is the Windows website.
Valves