Skip to main contentThis playbook addresses the common “I can’t reach this server” ticket, providing a logical flow to quickly isolate the point of failure.
Step 1: Check End-to-End Reachability (Ping)
Use the Looking Glass (Ping) tool to test connectivity to the destination IP address.
- If the ping succeeds, basic network reachability is confirmed. The problem is likely at a higher layer, such as a host-based firewall on the server or an application that is not running.
- If the ping fails, there is a network path or routing issue. Proceed to Step 2.
Step 2: Check the Route (Route Lookup)
Use the Looking Glass (Route Lookup) tool to search for the destination IP prefix in the routing table.
- If the route is present, the platform knows how to reach the destination, but something is blocking the path. Proceed to Step 4.
- If the route is missing, the platform has no path to the destination. The problem is with the routing protocol (BGP) or a missing static route. Proceed to Step 3.
Step 3: Verify L2/BGP Health (If Route is Missing)
- Navigate to the ARP table (Network -> Cloud Router -> ARPs).
- Look for an ARP entry corresponding to the BGP peer or next-hop router’s IP address.
- If there is no ARP entry, the issue is at Layer 2. Verify physical connectivity, VLAN tagging, and interface configurations.
- If there is a valid ARP entry, Layer 2 is working correctly. The problem is a Layer 3 BGP misconfiguration (e.g., incorrect ASN, mismatched password, route filtering policy).
Step 4: Trace the Path (If Route is Present)
- Use the Looking Glass (Traceroute) tool to trace the path to the destination. The output will show the last successful hop before the connection fails, which significantly narrows down the location of the problem.
