Difference Between Network Firewall and Web Application Firewall
By Stephen Bucaro
A Network Firewall controls access to the resources of a local network using rules to control
incoming and outgoing network traffic. It acts as a security barrier between a trusted network, such as the
local network (LAN), and an untrusted network, such as the Internet. Only traffic allowed by the firewall
rules is permitted onto the local network, all other traffic is denied. A firewall can be implemented
in either hardware or software.
A Web Application Firewall (WAF) is a firewall that monitors and allows or blocks data packets
as they travel to and from a Web application. A WAF inspects each packet at OSI Layer 7 and uses rules
to filter out harmful traffic. A WAF protects web applications against zero-day exploits, impersonation,
cross-site scripting (XSS), SQL injection, session hijacking, buffer overflows, and other known vulnerabilities.
WAFs are especially useful to companies that provide products or services over the Internet. A WAF can
be either network-based, host-based, or cloud-based.
Network-based WAFs can reduce latency because they are usually a hardware-based network appliance
installed locally. They allow replication of rules and settings across multiple appliances, making large
scale deployment and configuration easier.
Host-based WAFs may be integrated into the application code itself. This reduces and simplifies the
cost of implementation.
Cloud-based WAFs are easy to deploy because they are provided by a third-party. With a Cloud-based
WAF you pay a subscription fee and place responsibility for protecting an organization's web application
with the third-party provider.
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