WAF (Web Application Firewall)
A layer that inspects HTTP requests for attack patterns like SQL injection before they reach the application itself, complementing rather than replacing server hardening.
What a WAF actually looks at
A WAF inspects the content of HTTP requests, not just whether a connection should be allowed, checking for known attack patterns such as SQL injection attempts or cross-site scripting payloads before those requests ever reach the application.
Why it is a complement, not a substitute
A WAF catches many known attack patterns, but a genuinely vulnerable application can still be exploited through a request that does not match any known bad pattern. Fixing the underlying vulnerability still matters even with a WAF in place.
Frequently asked questions
Does a WAF replace the need to patch the application itself?
No. It reduces exposure while a fix is being developed or applied, but it is not a substitute for actually fixing the underlying vulnerability.
Is a WAF the same as a regular firewall?
No. A regular firewall controls network-level access based on IP and port; a WAF inspects the actual content of HTTP requests for application-level attack patterns.
Can a WAF block legitimate traffic by mistake?
Yes, particularly with overly strict rule sets; WAF rules typically need some tuning against real traffic to avoid false positives on legitimate requests.
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