Linux Firewall Open specific ports (iptables)

Iptables is a firewall under Linux and is also the service name.

Service iptables Status View firewall state

Service iptables start to turn on the firewall

Service iptables Stop shutting down the firewall

Service iptables Restart Restart firewall

Firewalls Open specific ports:

① file/etc/sysconfig/iptables

② Add:

-A rh-firewall-1-input-m state--state new-m tcp-p TCP--dport 8080-j ACCEPT

★ The number 8080 for open 8080 port, can also be changed to other ports ★

③ Restart the firewall

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Save settings for the firewall

Serivce iptables Save

View Iptables rules and numbers

IPTABLES-NL--line-number

Turn off all input FORWARD (forwards) output for all ports

Iptables-p INPUT DROP

Iptables-p FORWARD DROP

Iptables-p OUTPUT DROP

Open only 22 ports

Iptables-a input-p TCP--dport 22-j ACCEPT

Iptables-a output-p TCP--sport 22-j ACCEPT

Parameter explanation:

The –A parameter is seen as adding a rule

–P specifies what protocol we commonly use for the TCP protocol, and of course there are UDP, such as 53-port DNS

–dport is the destination port, when the data goes from outside to the server as the destination port

–sport data goes out of the server, it is used for the data source port

–J is designated as Accept-receive or DROP not receive

Disable an IP access

Iptables-a input-p tcp-s 192.168.1.2-j DROP

–s parameter is source (i.e. 192.168.1.2)

The back rejection is drop.

Delete Rule

Iptables-d INPUT 2

Delete the input chain number 2 rule

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Linux Firewall Open specific ports (iptables)