Network & Security

Traceroute Guide

Learn how to use traceroute to diagnose network issues

Calculator

What is Traceroute?

Traceroute is a network diagnostic tool that shows the path packets take from your computer to a destination server. It reveals every router (hop) along the way and measures the round-trip time (RTT) for each hop, helping you identify where network delays or failures occur.

Network DiagnosticsLatency AnalysisPath Discovery

The TTL (Time To Live) Mechanism

Traceroute exploits the TTL field in IP packets. TTL is decremented by 1 at each router. When TTL reaches 0, the router sends back an ICMP Time Exceeded message, revealing its identity.

Your PC
TTL=1
Router 1TTL=0, Reply!
TTL=2
Router 2TTL=0, Reply!
TTL=3
DestinationReached!

Step-by-Step Process

1
Send packet with TTL=1
The first router receives it, decrements TTL to 0, and sends back an ICMP Time Exceeded message
2
Send packet with TTL=2
Packet passes router 1, router 2 decrements TTL to 0 and replies
3
Increment TTL and repeat
Continue incrementing TTL until destination responds or max hops reached
4
Measure round-trip times
Record RTT for each hop to identify where delays occur in the path

Packet Types Used

ICMP (Windows)
Uses ICMP Echo Request packets. Most compatible but may be blocked by firewalls.
UDP (Unix Default)
Uses UDP packets to high ports. Can reveal different paths than ICMP.
TCP SYN
Uses TCP SYN packets. Useful when ICMP/UDP are blocked.

Windows built-in traceroute command using ICMP Echo Request packets

Basic Usage
tracert google.com
Available Flags
-d
Do not resolve IP addresses to hostnames (faster)
-h <max_hops>
Maximum number of hops to search for target (default: 30)
-w <timeout>
Timeout in milliseconds to wait for each reply
-j <host-list>
Loose source route along host-list
-4
Force using IPv4
-6
Force using IPv6
Example with Flags
tracert -d -h 20 google.com

Why cant browsers run traceroute?

Traceroute requires sending raw ICMP or UDP packets with custom TTL values - something web browsers are not allowed to do for security reasons. Browsers can only make HTTP/HTTPS requests. To run a real traceroute, you need to use your operating systems command line or an online tool that runs it server-side.

Quick Reference

Windows: tracert google.com

Linux/Mac: traceroute google.com

MTR (continuous): mtr google.com

How to Use

Trace the network path to any destination

1

Enter destination

Type the IP address or hostname to trace

2

Run traceroute

Click trace to map the network path to the destination

3

Analyze hops

Review each hop with response times to identify slow or failing segments

Frequently Asked Questions

Traceroute displays the network path packets take to reach a destination, showing each hop (router) along the way with its IP address, hostname, and response time. This helps identify where delays or failures occur in the network path.

Traceroute helps diagnose network connectivity issues, identify slow network segments, verify routing paths, troubleshoot high latency problems, and understand the geographic path your traffic takes to reach a destination server.

Asterisks indicate the router at that hop did not respond within the timeout period. This could mean the router is configured to not respond to traceroute packets (common for security), the packets were dropped, or there is severe congestion.

Ping only tests if a destination is reachable and measures round-trip time. Traceroute shows the complete path with every intermediate hop, helping pinpoint exactly where network problems occur rather than just confirming end-to-end connectivity.

Network & Security

IP lookup, DNS tools, SSL checker and security utilities

View all tools