The tracert command (or traceroute on Unix-like systems) is a network diagnostic tool used to track the route that packets take from your computer to a specified destination on an IP network. It displays the routers (hops) that packets pass through and the time it takes for each hop to respond.

Understanding Network Paths

This tool is invaluable for diagnosing network connectivity issues, identifying latency bottlenecks, and understanding the path your data travels across the internet. By examining the output, you can pinpoint where delays or failures might be occurring in the network path.

Traceroute Command Usage

Here are common ways to use the tracert command:

# Basic Usage: Trace route to a hostname
tracert [hostname]

# Trace route to an IP address
tracert [IP address]

# Specify the maximum number of hops to search for the target
tracert -h [max hops] [hostname]

# Set the timeout period (in milliseconds) for each reply
tracert -w [timeout] [hostname]

# Do not resolve IP addresses to hostnames (faster and shows raw IPs)
tracert -d [hostname]

# Example of combining options: trace route with no DNS resolution and specific timeout
tracert -d -w 1000 [hostname]

# Run a trace route using a specific source IP address
tracert -s [source IP] [target hostname]

# Run a trace route with IPv6 (use tracert6 on older Windows versions if available)
tracert -6 [hostname]

# Use Internet Control Message Protocol (ICMP) echo request messages (often default on Windows)
tracert -4 [hostname]

Interpreting Traceroute Results

The output of tracert typically shows a list of hops, each with three round-trip times (in milliseconds) and the IP address or hostname of the router at that hop. If a hop times out, it's indicated by asterisks (* * *). This information helps in diagnosing network performance and connectivity problems.

External Resources

• MDN Web Docs: Network Information API
• IANA Protocol Numbers
• RFC 791: Internet Protocol