SG Cisco ACL Analyzer

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SanchitGurukul · Network Security Tools

Cisco ACL Analyzer

Analyze Cisco IOS / IOS-XE IPv4 access lists for structure, duplicates, shadowing, broad permits, risky services, unreachable rules, and likely cleanup opportunities.

Local analysis
Privacy: ACL text is analyzed locally in your browser. It is not uploaded, stored, or transmitted by this tool.
Important: Treat results as engineering assistance, not an automatic change recommendation. ACL behavior depends on platform, interface direction, routing, NAT, object-groups, software release, established sessions and features outside the ACL itself. Validate changes in a lab or approved maintenance window.

ACL Input

How to use the analyzer

1. Collect the ACL

Copy the relevant show running-config | section access-list, named ACL section, or sanitized configuration.

2. Analyze

Paste the ACL and select Analyze ACL. Review parse warnings before relying on findings.

3. Review high-impact findings

Prioritize broad permits, exposed management services, duplicate entries, complete shadows and rules after unconditional termination.

4. Simulate flows

Test representative source/destination/protocol/port combinations against first-match behavior.

5. Validate operational context

Confirm ACL direction, interface, routing, NAT order, object-groups, platform behavior and current traffic before editing.

6. Change safely

Use configuration review, peer approval, backups, rollback plans and post-change verification.

Examples

Internet-facing HTTPS ACL
ip access-list extended INTERNET-IN
 10 permit tcp any host 203.0.113.10 eq 443
 20 deny ip any any log
Management ACL
ip access-list standard MGMT-SOURCES
 10 permit 10.20.30.0 0.0.0.255
 20 deny any log
Potential shadowing
ip access-list extended APP
 10 permit ip 10.0.0.0 0.255.255.255 any
 20 permit tcp host 10.10.10.20 host 172.16.1.20 eq 443
 30 deny ip any any

Warnings & limitations

  • This analyzer performs static, local configuration analysis. It does not read device state, routing tables, NAT tables, interface bindings, session tables, counters or live traffic.
  • Shadowing and overlap detection is strongest for IPv4 addresses expressed as any, host, and contiguous wildcard masks. Non-contiguous wildcard masks are treated conservatively.
  • Object-group references are identified but not recursively resolved unless their members are present in a supported form. Results involving unresolved groups are marked accordingly.
  • Service names are mapped to common ports for convenience. Device-specific aliases or customized services may differ.
  • An established TCP entry is interpreted only as a rule option; the analyzer does not emulate every platform-specific TCP flag behavior.
  • Rule risk is contextual. A broad permit may be intentional inside a trusted segment, while a narrow rule may still be unsafe in the wrong location.
  • Do not paste secrets, credentials, private keys or unrelated confidential configuration. Sanitize configurations before using any browser-based analysis tool on shared systems.
© SanchitGurukul · Technology • Education • Innovation · For educational, laboratory, troubleshooting and authorized administrative use.

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