what inbound connection are safe ?

hi what inbound connection are safe or what inbound connection are malicious?
why we should had inbound connection

thx

Generally speaking, you should not have any inbound connection unless you wanna remotelly control you pc (for example, if you ask someone from GeekBuddy to help you with CIS).
Usually in CFW there is a global rule to block any inbound connection

If you are hosting a web or FTP server on your network, for example, you would want to allow incoming connections on a port by port basis. Also for things like file sharing, remote desktop, they require the firewall to allow incoming connections too. Firewall rules are what makes incoming connections allowed or not and what programs are allowed to listen for certain incoming requests are based on the application rules.

Malicious incoming connections could happen if you were infected with a virus or trojan horse, which opens ports so a hacker could gain access remotely.

So, any inbound connection could be malicious or safe. It depends.