# Gtrace Path Analysis

> Network path tracing and monitoring — traceroute with MPLS/ECMP/NAT detection, continuous MTR monitoring, and distributed GlobalPing probes from 500+ worldwide locations. Use when tracing the path to a destination, diagnosing slow network routes, detecting MPLS or ECMP load balancing, running MTR for intermittent packet loss, or testing reachability from global vantage points.

- Skill: `gabrielmoreira/gtrace-path-analysis` (Agent Skill)
- Install (CLI): `npx skillmds@latest add gabrielmoreira/gtrace-path-analysis`
- Raw SKILL.md: https://api.skillmd.com/api/skills/gabrielmoreira/gtrace-path-analysis/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- License: Apache-2.0
- Author: gabrielmoreira (https://skillmd.com/u/gabrielmoreira)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/gabrielmoreira/gtrace-path-analysis

---


# Network Path Analysis with gtrace

## How to Call the gtrace MCP Tools

```bash
python3 $MCP_CALL "gtrace mcp" TOOL_NAME '{"param":"value"}'
```

## When to Use

- Trace the path between two endpoints and identify each hop (router, latency, loss)
- Detect MPLS labels, ECMP load balancing, and NAT translation points along the path
- Monitor a path continuously with MTR to identify intermittent packet loss or latency spikes
- Run distributed traceroutes from 500+ GlobalPing probe locations worldwide to compare paths from different vantage points
- Verify transit providers, peering, and routing policy by inspecting AS-level path data
- Troubleshoot asymmetric routing, suboptimal paths, or blackholes

## Available Tools

| Tool | Purpose | Requirements |
|------|---------|-------------|
| `traceroute` | Advanced traceroute with MPLS, ECMP, and NAT detection | cap_net_raw |
| `mtr` | Continuous MTR monitoring with packet loss and jitter stats | cap_net_raw |
| `globalping` | Distributed traceroute/ping from 500+ worldwide probe locations | Internet access (optional GLOBALPING_API_KEY) |

## Workflow: Path Troubleshooting

When asked "why is traffic slow to X?" or "trace the path to X":

### Step 1: Traceroute

Run an advanced traceroute to see every hop, latency, and any MPLS/ECMP/NAT indicators.

```bash
python3 $MCP_CALL "gtrace mcp" traceroute '{"target":"8.8.8.8"}'
```

For IPv6:

```bash
python3 $MCP_CALL "gtrace mcp" traceroute '{"target":"2001:4860:4860::8888"}'
```

### Step 2: Continuous Monitoring with MTR

If the traceroute shows packet loss or high latency at a specific hop, run MTR to monitor continuously and confirm the problem is persistent.

```bash
python3 $MCP_CALL "gtrace mcp" mtr '{"target":"8.8.8.8","count":100}'
```

### Step 3: Global Perspective

Compare paths from multiple worldwide locations to determine if the issue is local or global.

```bash
python3 $MCP_CALL "gtrace mcp" globalping '{"target":"8.8.8.8","from":"US,EU,Asia"}'
```

## Workflow: MPLS Path Verification

Verify MPLS label-switched paths and label stacks along the path:

```bash
python3 $MCP_CALL "gtrace mcp" traceroute '{"target":"10.0.0.1"}'
```

Look for MPLS label information in the hop details. Useful for verifying traffic engineering and MPLS VPN paths.

## Workflow: ECMP Load Balancing Verification

Detect if traffic is being load-balanced across multiple equal-cost paths:

```bash
python3 $MCP_CALL "gtrace mcp" traceroute '{"target":"192.168.1.1"}'
```

ECMP detection reveals when multiple next-hops exist at a given TTL, indicating load balancing.

## Tool Parameters

### traceroute
- `target` (required): IP address or hostname to trace

### mtr
- `target` (required): IP address or hostname to monitor
- `count` (optional): Number of probe rounds to send

### globalping
- `target` (required): IP address or hostname to probe
- `from` (optional): Comma-separated list of probe locations (countries, cities, regions, ASNs)

## Output Format

All tools return structured results including:
- **traceroute** — hop number, IP, hostname, RTT per probe, MPLS labels, ECMP paths, NAT detection
- **mtr** — hop number, loss%, sent/recv counts, best/avg/worst/stdev RTT
- **globalping** — per-probe-location results with path data, useful for global path comparison

## Important Rules

- Traceroute and MTR require `cap_net_raw` capability on the gtrace binary (set during install)
- GlobalPing uses the public GlobalPing API — set `GLOBALPING_API_KEY` for higher rate limits
- Always start with a single traceroute before running continuous MTR
- Use GlobalPing to differentiate local vs global path issues
- Cross-reference hop IPs with `asn_lookup` and `geo_lookup` from gtrace-ip-enrichment skill for full context
- Record all path analysis in GAIT