Can't open a port

Question

I need to run an app on my computer which connects to local port 49100. So everything runs on one computer.

I tried adding rules to gufw, firestarter, manually:

sudo iptables -A INPUT -p tcp --dport 49100 -j ACCEPT

But when I look at opened ports 49100 is not listed! And my app cannot connect to local debugger therefore. I ran:

sudo netstat -anltp | grep "49100"

it returns nothing.

Answer 1

Generally, firewalls don't block local traffic. If your client application connects to port 49100, it expects to find a service (whatever that is) there. So, you need to start the server application (whatever that is) that listens on port 49100 and provides with the service that the client application is expecting to find there.

49100 is not a port associated with a well known service, it is not registered as such at IANA (the organisation that assigns numbers on the internet), so we probably won't able to tell you more unless you tell us what that application is. In any case, you may find some information in that application documentation.