The default CentOS 5.6 firewall configuration does not allow Apache httpd traffic on port 80. In order to open the port for utilization, a change must be made to the firewall configuration.
iptables -I INPUT -p tcp -m tcp ––dport 80 -j ACCEPT
To open a hole for VNCServer (running on display 20):
iptables -I INPUT -p tcp -m tcp ––dport 5920 -j ACCEPT
To open a hole for VNCServer (running on display 20) web base interface:
iptables -I INPUT -p tcp -m tcp ––dport 5820 -j ACCEPT
To display the openings you’ve created in your firewall:
iptables -L INPUT -n ––line-numbers
To remove a line entry from your iptables file (for example, entry #3):
iptables -D INPUT 3
Notes:
There are two dashes in front of parameters such as “––line-numbers” and “––dport.”
The iptables service must be saved, and restarted before changes take effect.
service iptables save
service iptables restart
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