traceroute is a computer network tool used to determine the route taken by packets across an IP network. An IPv6 variant, traceroute6, is also widely available.

The tracert tool is available on practically all Unix-like operating systems. Variants with similar functionality are also available, such as tracepath on modern Linux installations and tracert on Microsoft Windows operating systems. Windows NT-based operating systems also provide pathping, which provides similar functionality.


Traceroute works by increasing the "time-to-live" value of each successive batch of packets sent. The first three packets sent have a time-to-live (TTL) value of one (implying that they are not forwarded by the next router and make only a single hop). The next three packets have a TTL value of 2, and so on. When a packet passes through a host, normally the host decrements the TTL value by one, and forwards the packet to the next host. When a packet with a TTL of one reaches a host, the host discards the packet and sends an ICMP time exceeded (type 11) packet to the sender. The traceroute utility uses these returning packets to produce a list of hosts that the packets have traversed en route to the destination. The three timestamp values returned for each host along the path are the delay (aka latency) values typically in milliseconds (ms) for each packet in the batch. If a packet does not return within the expected timeout window, a star (asterisk) is traditionally printed. Traceroute may not list the real hosts. It indicates that the first host is at one hop, the second host at two hops, etc. IP does not guarantee that all the packets take the same route. Also note that if the host at hop number N does not reply, the hop will be skipped in the output.

On modern Unix and Linux-based operating systems, the traceroute utility by default uses UDP datagrams with destination ports number from 33434 to 33534. The traceroute utility usually has an option to specify use of ICMP echo request (type 8) instead, as used by the Windows tracert utility. If you have a firewall and if you want traceroute to work from both machines (Unix/Linux and Windows) you will need to allow both protocols inbound through your firewall (UDP with ports from 33434 to 33534 and ICMP type 8).

There are also traceroute implementations that use TCP packets, such as tcptraceroute or lft. pathping is a utility introduced with Windows NT that combines ping and traceroute functionality. mtr (My traceroute) is an enhanced version of ICMP traceroute which is available for Unix and Windows systems. All implementations of traceroute rely on ICMP (type 11) packets being sent to the originator.


Estonia to the United States. ( to (

Windows command : tracert

Linux or Mac OS X command : traceroute

AS/400 command : QSYS/TRCTCPRTE RMTSYS('')



Traceroute is often used for network troubleshooting. By showing a list of routers traversed, it allows the user to identify the path taken to reach a particular destination on the network. This can help identify routing problems or firewalls that may be blocking access to a site. Traceroute is also used by penetration testers to gather information about network infrastructure and IP ranges around a given host. It can also be used when downloading data, and if there are multiple mirrors available for the same piece of data, one can trace each mirror to get a good idea of which mirror would be the fastest to use.

ecurity concerns

Supplying such detailed information about the pathways taken was considered acceptable and convenient in the early days of the Internet, but later was considered questionable for privacy and security reasons. Traceroute information has been frequently used by crackers as a way to acquire sensitive information about a company's network architecture. By using the traceroute command, a cracker can quickly map out what nodes are available on a company's network architecture and exploit vulnerable or compromised nodes/computers.

For these reasons, while traceroute was widely used during the early days of the Internet, by the 1990s many Internet sites were blocking traceroute requests. fact|date=July 2008 Usually, however, traceroute will function up to the borders of blocked sites, revealing the path to a given site, but in many cases not the network within that site.


The traceroute man page states that the original traceroute program was written by Van Jacobson in 1987 from a suggestion by Steve Deering, with particularly cogent suggestions or fixes from C. Philip Wood, Tim Seaver and Ken Adelman.

ee also

* Layer Four Trace, a more modern traceroute (IP network tracing) implementation that supports a multitude of layer-4 protocols
* mtr (My traceroute)
* Pathping
* List of Unix programs
* List of DOS commands

External links

* RFC 1393: Traceroute using an IP Option Internet RFC
* RFC 792: Internet Control Message Protocol (ICMP)
* [ traceroute man page]
* [] : monthly updated list of online traceroutes
* VivilProject Traceroute List
* [ Traceroute Wiki] : hundreds of traceroute servers, sorted by Autonomous System Number
* [ GeoTrace] - Geographically map a hostname or domain with traceroute
* [ Graphical TraceRoute for Windows]


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Traceroute — ist ein Computerprogramm, mit dem ermittelt werden kann, über welche IP Router Datenpakete bis zum Ziel Host vermittelt werden. Traceroute sendet dazu mehrfach Pakete mit einer veränderten und jeweils um 1 erhöhten Time to live (TTL), beginnend… …   Deutsch Wikipedia

  • Traceroute — это служебная компьютерная программа, предназначенная для определения маршрутов следования данных в сетях TCP/IP. Traceroute основана на протоколе ICMP. Графический интерфейс к traceroute в gnome nettool в Ubuntu 6.10 …   Википедия

  • traceroute — Traceroute  это служебная компьютерная программа, предназначенная для определения маршрутов следования данных в сетях TCP/IP. Traceroute может использовать разные протоколы передачи данных в зависимости от операционной системы устройства.… …   Википедия

  • Traceroute — est un outil réseau qui permet de suivre le chemin qu un paquet de données (paquet IP) va prendre pour aller d une machine A à une machine B. Par défaut, le paquet peut passer sur Internet mais le chemin emprunté par le paquet peut varier, en cas …   Wikipédia en Français

  • Traceroute — es una consola de diagnóstico de redes de Linux que permite seguir la pista de los paquetes que vienen desde un host (punto de red) host. Se obtiene además una estadística del RTT o latencia de red de esos paquetes, lo que viene a ser una… …   Wikipedia Español

  • traceroute — est un programme utilitaire qui permet de suivre les chemins qu un paquet de données (paquet IP) va prendre pour aller de la machine locale à une autre machine connectée au réseau IP. Sommaire 1 Fonctionnement 2 Exemple sous Unix 3 Exemple sous… …   Wikipédia en Français

  • Traceroute — Traceroute,   ein Hilfsprogramm, das den Pfad anzeigt, den ein Datenpaket in einem paketvermittelten Netzwerk durchläuft. Es ist neben dem Programm Ping eines der wichtigsten Werkzeuge, um Verbindungen in TCP/IP Netzen zu analysieren. Im World… …   Universal-Lexikon

  • Traceroute — es una herramienta de diagnóstico de redes que permite seguir la pista de los datagramas que van desde un host (punto de red) a otro. Se obtiene además una estadística de las velocidades de transmisión de esos paquetes …   Enciclopedia Universal

  • traceroute — ● np. m. ►INTERNET Utilitaire permettant de déterminer le trajet emprunté par vos paquets IP sur l Internet, d hôte en hôte. L expression faire un traceroute signifie utilise ce programme pour savoir par où vont les paquets vers un hôte …   Dictionnaire d'informatique francophone

  • Traceroute — Routine, die den Weg eines über das Internet übertragenen Datenpakets aufzeigt. Bei einem Traceroute werden alle Server, die an der Datenübertragung beteiligt sind, aufgelistet. ICMP, IP Adresse, Ping, Server, tracing …   Online-Wörterbuch Deutsch-Lexikon

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”