Linux Open or Close ports

One, see which ports are open NETSTAT-ANP

Second, turn off the port number: iptables-a input-p TCP--drop port number-j drop

Iptables-a output-p TCP--dport port number-j DROP

Third, start the slogan: iptables-a input-ptcp--dport port number-j ACCEPT

Four, the following is the use of the Linux Open Port command.

Nc-lp & (Open 23 port, Telnet)

Netstat-an | grep 23 (see if 23 ports are open)

Five, Linux open port command every open port, you need to have the appropriate listener to

Linux Open or Close ports