Waf

Overview A firewall and a web application firewall (WAF) both filter traffic, but they operate at different layers of the stack. A firewall makes allow/deny decisions based on IP and port, while a WAF inspects the actual HTTP payload of requests to catch application-layer attacks like SQL injection and XSS. Most production environments deploy both, since neither can see what the other is built to catch. Comparison Diagram FirewallWAFRaw network trafficTCP SYN, dst port 22FirewallL3/L4: IP, port, protocolAllow 443Block 22Cannot see inside theHTTP request bodyHTTP requestGET /login?id=1' OR '1'='1WAFL7: URL, headers, bodyAllow normalBlock SQLiDecrypts TLS to inspectthe request payloadLayered defense: firewall blocks unauthorized access, WAF blocks malicious payloads Comparison Table Aspect Firewall WAF OSI layer inspected Network/transport (L3/L4) Application (L7) Traffic filtered All IP traffic, any protocol or port HTTP/HTTPS requests only Inspection criteria Source/destination IP, port, protocol, connection state URL, headers, cookies, and request body content Rule basis Static allow/deny rules and ACLs Signature and behavioral rules for known attack patterns Typical deployment point Network perimeter or between internal subnets In front of or alongside web servers/load balancers Attacks stopped Port scans, unauthorized network access, network-layer floods SQL injection, XSS, CSRF, other OWASP Top 10 exploits Encrypted traffic handling Sees only packet headers, not TLS-encrypted payload Typically terminates TLS to inspect decrypted HTTP content Maintenance cadence Relatively static rule sets, infrequent changes Frequent signature updates as new exploits are discovered Key Differences A firewall filters at the network layer using IP and port, while a WAF filters at the application layer using HTTP content. Firewalls control which connections are permitted; WAFs inspect the payload within connections already allowed through. A WAF typically must decrypt TLS to read requests, whereas a firewall generally cannot see inside encrypted traffic. The two are complementary controls, not substitutes — each blocks a different class of attack the other misses. When to Use Each Firewall ...