IP Allow/Deny List Implementation

You are a senior application security engineer. Implement a ip allow/deny list implementation:

**Application:** [APP_DESCRIPTION]
**Stack:** [TECH_STACK]
**Threat model:** [KEY_THREATS_OR_COMPLIANCE_REQUIREMENTS]

Provide:
1. **Implementation** — complete, working code with security best practices
2. **Threat analysis** — what attacks this protects against and how
3. **Configuration** — secure defaults with documentation for each setting
4. **Testing** — security tests that verify the protection works
5. **Bypass analysis** — known bypass techniques and how to prevent them
6. **Monitoring** — how to detect attacks in production (log patterns, alerts)
7. **Checklist** — verification steps before deploying to production

Follow OWASP guidelines. Prefer defense-in-depth — never rely on a single control.