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Difficulty: MediumTroubleshooting Routing, Default Gateways, and ACLs

A client workstation on VLAN 10 (192.168.10.45/24192.168.10.45/24) cannot reach a database server located on VLAN 30 (10.0.30.100/2410.0.30.100/24) across an enterprise Layer 3 switch with Access Control Lists (ACLs). Following the CompTIA network troubleshooting methodology, place the diagnostic and remediation actions in the correct sequential order from first step to last step.

  1. 1Verify local host network settings by checking the workstation's IP address, subnet mask, and default gateway configuration.
  2. 2Ping the configured default gateway address (192.168.10.1192.168.10.1) from the client workstation.
  3. 3Execute a `traceroute` from the client workstation to the target IP (10.0.30.10010.0.30.100).
  4. 4Inspect the Layer 3 switch routing table and configured ACLs (`show ip route` and `show ip access-lists`).
  5. 5Apply the missing route or modify the ACL permit rule, then test database connectivity to verify resolution.

Answer

The correct logical order begins with checking local host configuration, testing local default gateway reachability, performing a traceroute to identify the blocking network hop, inspecting the switch routing table and ACLs at that hop, and finally applying the configuration fix and verifying service connectivity.
The correct sequence follows the CompTIA troubleshooting methodology by starting at the local host (verifying host IP settings), testing the local link to the default gateway, executing path analysis to pinpoint the failure point (traceroute), inspecting infrastructure configuration files (routes and ACLs), and concluding with remediation and verification.

Step-by-Step Solution

1
Check host IP configuration
Confirms the host has valid IP settings and points to the correct gateway IP.
Always eliminate basic host-level misconfigurations before investigating network infrastructure.
2
Test local default gateway reachability using ICMP ping
Verifies Layer 2 link integrity and local router interface accessibility.
If the local gateway does not respond, remote routing cannot be evaluated.
3
Perform path tracing with traceroute
Identifies the exact intermediate router hop where communication fails.
Traceroute narrows down the problem domain to a specific gateway or filtering device.
4
Examine device routing tables and active ACL statements
Reveals root cause such as a missing route entry or an explicit/implicit ACL block.
Diagnoses the precise administrative or policy configuration issue on the failing node.
5
Remediate configuration and perform end-to-end test
Restores traffic flow and confirms application access is functional.
Finalizes the troubleshooting methodology cycle by validating system functionality.

Key Concept

Sequential isolation of routing, gateway, and ACL issues using CompTIA troubleshooting methodology
Estimated Time:2m 0s
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Topics

Troubleshooting Routing, Default Gateways, and ACLs

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