Blocking port 80 using IPTABLES in RHEL

This is just basic example using iptables, it needs more practice since it is complicated task.

Make sure port 80 is accessible on the server.

# telnet 80

to check iptables contents:

# less /etc/sysconfig/iptables

For blocking port 80 using command line

# iptables -I INPUT -p tcp --dport 80 -j REJECT

Save the configuration

# service iptables save

Saving firewall rules to /etc/sysconfig/iptables: [ OK ]

Restart the service

# service iptables restart

Flushing firewall rules: [ OK ]

Setting chains to policy ACCEPT: filter [ OK ]

Unloading iptables modules: [ OK ]

Applying iptables firewall rules: [ OK ]

Loading additional iptables modules: ip_conntrack_netbios_n[ OK ]

Make sure port 80 is not accessible now.

# telnet 80

To remove the configuration enter the following command, save and restart the service:

# iptables -D INPUT -p tcp --dport 80 -j REJECT

Now, you should access port 80 again.