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Zorluk: KolayTroubleshooting Routing, Default Gateways, and ACLs

A workstation on a corporate network cannot reach a web server located on a remote subnet. Arrange the following diagnostic steps in the correct logical sequence to systematically isolate whether the connectivity issue stems from local TCP/IP settings, the local default gateway, path routing, or router Access Control Lists (ACLs).

  1. 1Ping the local loopback address (127.0.0.1127.0.0.1) to verify that the local workstation network stack is functional.
  2. 2Ping the local default gateway address to confirm Layer 2 and Layer 3 reachability within the local subnet.
  3. 3Execute a `traceroute` command to the remote web server IP address to locate the specific hop where packet loss occurs.
  4. 4Inspect the routing table and active interface Access Control Lists (ACLs) on the router at the failure hop.

Cevap

The correct sequence begins with testing the local TCP/IP stack (127.0.0.1127.0.0.1), followed by pinging the default gateway, executing a traceroute to locate the failing hop, and finally inspecting the router table and ACL entries at the failure point.
Structured network troubleshooting progresses from inside to outside: verifying the local host TCP/IP stack first, testing the local default gateway second, running path tracing to pinpoint intermediate failure hops third, and examining router configuration state (routes and ACLs) at the point of failure last.

Adım Adım Çözüm

1
Ping the loopback address (127.0.0.1127.0.0.1).
Confirms the host network driver and protocol stack are operational.
Eliminates local host software corruption before testing physical/network link reachability.
2
Ping the default gateway IP address.
Verifies local subnet connectivity and gateway IP configuration.
Determines whether the issue is restricted to the local broadcast domain or gateway reachability.
3
Run traceroute to the target destination address.
Identifies the exact gateway hop where path forwarding stops.
Isolates the network boundary between functional intermediate routers and the failing node.
4
Check routing tables and ACL rules on the failing hop router.
Reveals missing routes or filtering rules blocking destination traffic.
Provides the root cause configuration detail required to restore network traffic flow.

Anahtar Kavram

Standard Network Troubleshooting Flow for Gateway, Routing, and ACL Faults
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