Everything you need to know about traceroute — from command-line usage to network troubleshooting.
What is Traceroute?
Traceroute is a fundamental network diagnostic command that maps the precise route Internet packets travel from source to destination. Operating by sending probe packets with incrementally increasing Time-To-Live (TTL) values, it forces each router along the path to return an ICMP "Time Exceeded" response, revealing its IP address and round-trip latency. This hop-by-hop visibility is invaluable for identifying where network congestion, high latency, or outright packet loss originates — whether that is within your ISP, a transit provider, or the destination network itself. Our Traceroute Online tool performs this same diagnostic from our server infrastructure, eliminating the need for any software installation and making professional-grade network path analysis accessible directly from your browser.
Traceroute on Linux
On Linux systems, the traceroute command is your primary tool for network path analysis. Installed via sudo apt install traceroute on Debian/Ubuntu or sudo yum install traceroute on CentOS/RHEL, it defaults to UDP probes but supports ICMP with the -I flag and TCP with -T. The alternative tracepath command requires no root privileges and auto-discovers MTU along the path. For modern Linux systems, mtr (My Traceroute) combines ping and traceroute into a continuously updating display, making it ideal for monitoring flapping routes or intermittent packet loss in real time.
Traceroute on Windows (tracert)
Windows ships with tracert (Trace Route), accessible through Command Prompt or PowerShell. Unlike Linux, Windows tracert exclusively uses ICMP Echo Request packets, which may be filtered by firewalls that permit UDP/TCP traffic. Run it with tracert google.com or customise with flags: -h 64 sets maximum hops, -w 5000 adjusts the timeout in milliseconds, and -d skips reverse DNS to speed up results. PowerShell users can leverage the Test-NetConnection cmdlet for additional network diagnostics alongside traditional tracert commands.
Traceroute on macOS
macOS includes traceroute in its Network Utilities suite, accessible via Terminal. macOS defaults to UDP probes on ports 33434–33524, but ICMP mode is activated with sudo traceroute -I hostname. The graphical Network Utility app (Applications → Utilities) provides a user-friendly traceroute interface without the Terminal. For power users, mtr is installable via Homebrew (brew install mtr) and provides real-time continuous path monitoring. macOS Monterey and later include enhanced network diagnostics through the built-in Wireless Diagnostics tool, which performs background route tracing automatically.
Interpreting Results
Understanding traceroute output is essential for effective network troubleshooting. Each line represents one router (hop) with three RTT measurements in milliseconds. Low RTT (<20ms) indicates fast, local connections; medium RTT (20–80ms) suggests regional hops; high RTT (>80ms) flags intercontinental or congested links. Asterisks (* * *) mean a router did not respond — often due to ICMP filtering, not a broken link. A sudden large RTT increase between consecutive hops pinpoints the congested segment. Consistent high RTT from a specific hop onwards indicates the problem lies at or beyond that router.
Common Use Cases
Network engineers and system administrators rely on traceroute daily: diagnosing why a website loads slowly (identifying the congested hop), verifying that traffic routes correctly through a VPN or CDN, confirming BGP routing changes have propagated, and troubleshooting asymmetric routing where outbound and inbound paths differ. DevOps teams use traceroute to validate latency between cloud regions (AWS, GCP, Azure) and identify whether issues are within the cloud provider's backbone or the public internet. Web developers use it to verify that CDN edge nodes are being reached and to benchmark origin server latency from different geographic locations.