Opening Web Server Ports on CentOS

A web server on a VPS requires port configurations to allow public access to hosted websites. The specific ports that need to be opened within iptables are port 80 (HTTP) and port 443 (HTTPS). There are two methods to configure this setup:

1: Editing the /etc/sysconfig/iptables File

vi /etc/sysconfig/iptables

# Firewall configuration written by system-config-firewall
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state –state ESTABLISHED,RELATED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -m state –state NEW -m tcp -p tcp –dport 22 -j ACCEPT
-A INPUT -m state –state NEW -m tcp -p tcp –dport 80 -j ACCEPT
-A INPUT -m state –state NEW -m tcp -p tcp –dport 443 -j ACCEPT
-A INPUT -j REJECT –reject-with icmp-host-prohibited
-A FORWARD -j REJECT –reject-with icmp-host-prohibited

2: Using the Command Line Interface (CLI)

iptables -A INPUT -p tcp -m tcp --dport 80 -j ACCEPT
iptables -A INPUT -p tcp -m tcp --dport 443 -j ACCEPT
iptables -I INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

Saving and Restarting iptables

service iptables save

Next, restart the iptables service to apply the changes:

service iptables restart

Verifying the Firewall Settings

iptables -L

Chain INPUT (policy ACCEPT)
target     prot opt source               destination
ACCEPT     all  —  anywhere             anywhere            state RELATED,ESTABLISHED
ACCEPT     icmp —  anywhere             anywhere
ACCEPT     all  —  anywhere             anywhere
ACCEPT     tcp  —  anywhere             anywhere            state NEW tcp dpt:ssh
ACCEPT     tcp  —  anywhere             anywhere            state NEW tcp dpt:http
REJECT     all  —  anywhere             anywhere            reject-with icmp-host-prohibited

Once verified, you can test the connection by accessing the website hosted on your server via any web browser.