docs(notes): add 2025-03-20 traceroute proxy documentation

Author: lzwjava

notes/2025-03-20-traceroute-proxy-en.md

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+---
+title: Does Traceroute Use a Proxy?
+lang: en
+layout: post
+audio: false
+translated: false
+generated: true
+---
+
+Traceroute itself does not inherently use a proxy. Let me explain how traceroute works and where proxies might come into play:
+
+### What Traceroute Does
+Traceroute is a network diagnostic tool used to map the path that data packets take from your device to a target destination (like a website or server). It works by:
+- Sending packets with incrementally increasing Time-to-Live (TTL) values.
+- Each router along the path decrements the TTL, and when it hits zero, the router sends back an "ICMP Time Exceeded" message.
+- This process reveals the IP addresses of the routers (hops) between you and the destination.
+
+By default, traceroute operates directly from your device to the target, using your network connection without involving proxies.
+
+### Proxies and Traceroute
+A proxy is an intermediary server that routes your traffic through itself before reaching the destination. Traceroute doesn’t use a proxy as part of its core functionality, but proxies can affect the results you see in specific scenarios:
+
+1. **If Your Connection Uses a Proxy**:
+   - If your internet traffic is configured to go through a proxy (e.g., via a browser or system-wide proxy settings), traceroute might still bypass it because it operates at a lower network level (typically ICMP or UDP packets, not HTTP). Most proxies handle higher-level protocols like HTTP/HTTPS, not raw ICMP traffic.
+   - However, if your network forces *all* traffic—including ICMP—through a proxy or VPN, the traceroute path will start at your device, hit the proxy or VPN server first, and then proceed to the destination. The initial hop(s) would reflect the proxy’s IP instead of your local router.
+
+2. **Traceroute Through a Remote Machine**:
+   - You can run traceroute from a remote server (e.g., via SSH) that might be behind a proxy or in a different network. In this case, the traceroute reflects the path from that server to the target, not your local machine, and any proxy in that setup could influence the route.
+
+3. **Network Configurations**:
+   - Some corporate or restricted networks use proxies or gateways that intercept and reroute all traffic, including traceroute packets. Here, the traceroute might show the proxy as an early hop, masking the true path beyond it.
+
+### Short Answer
+Traceroute doesn’t use a proxy by design—it’s a direct network tool. But if your network or device is configured to route traffic through a proxy or VPN, that proxy can appear in the traceroute path as a hop. Normally, though, traceroute operates independently of proxies, showing the raw network route from your point of origin to the destination.
+
+If you’re asking about a specific setup, feel free to clarify!