The web traffic on port 80 (http on port 80) of the firewall should be allowed from the internet to the web server. Generally, this is done through the rules configuration. It will basically not allow any traffic from the Internet to the webserver since there is a rule of implicit deny on most of the firewall, so go to the rules configuration and add a new rule in this way:
Source- Any
Destination- IP of webserver
Port: 80 (if configured otherwise, than custom port)
Action: Allow
One advantage of a two-firewall configuration is added defense-in-depth. With two firewalls, an attacker would need to bypass both firewalls to gain access to the network, providing an extra layer of protection. This can be especially useful in protecting against advanced attacks or minimizing the impact of a firewall compromise.
Usually software but some hardware firewall devices are produced.
Back to back
There are several internet security firewalls that could be considered famous. They include Zone Alarm, McAfee Firewall, TinyWall and Comodo Firewall.
the person who invented firewalls was David Pensak
stateful packet inspection
Firewall
Single point of failure
Cisco Systems and Techworld offer load balancer firewalls. Coyotepoint offers a free download of a load balancer firewall.
The best free firewall is the one built on to most computers. Better firewalls cost a lot of money. Software that claim to be free and better than built-in firewalls are usually spam or malware.
Firewalls are not 100% accurate, as newly created viruses can slip through without detection. Usually, though, firewalls will be updated as regularly as possible to block each new kind of virus. A firewall is only as strong as the person who configures it.
Download some of the best Firewalls like Comodo Firewall,Avast firewall etc to keep your ps safe from hackers.