> ## Documentation Index
> Fetch the complete documentation index at: https://docs.zayo.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Can't reach this server

This 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.