How to open a port on linux

sharad · 01-09-2007, 06:15 AM

Hi all,
Could anybody please tell me how to open a port which is running an
unknown process.

For example, if I want to open a ftp port then its easy because we know the service whcih runs on that port. we can do this just by starting the service.

But, if I want to open a port say 44000, then how to go for it.

I executed following iptables rule for opening the port.

iptables -A INPUT -i eth0 -p tcp --sport 32769 -m state --state ESTABLISHED -j ACCEPT

but nmap is saying that the port is closed.

nmap -p 44000 -sS localhost

I would appreciate if you could answer to my query.

Thanks & Regards,

Sharad.

stress_junkie · 01-09-2007, 06:40 AM

An open port means that there is some application listening for connect requests on that port and responding when connect requests are detected. Configuring the firewall to allow connect requests on that port is the first step. The next step is to configure some software to do something when a connect request is received.

amitsharma_26 · 01-09-2007, 07:32 AM

Quote:

Originally Posted by sharad

I executed following iptables rule for opening the port.

iptables -A INPUT -i eth0 -p tcp --sport 32769 -m state --state ESTABLISHED -j ACCEPT

but nmap is saying that the port is closed.

nmap -p 44000 -sS localhost

Sharad i really first of all dont see any sense in the inter-connection of these two commands. Second iptables only stand infront of your service(port) & nothin else. It doesnt open or close a port; it actually do the filtering part. You got to run the service at your box if you want to open the port.