Tuesday, June 1, 2010

Traceroute in Windows.

What is Traceroute in Windows ?

The traceroute utility checks how many "hops" (transfers through other computers on a network) it takes for your computer to contact another computer. You can use traceroute if you know the other computer's IP address, web site address, or name (e.g.,, www.citibank.co.in).

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, or an echo reply (type 0) if its IP address matches the IP address that the packet was originally sent to. The traceroute utility uses these returning packets to produce a list of hosts that the packets have traversed in transit 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.

At the command prompt, if you enter tracert www.citibank.co.in , you should see something similar to the following screenshot.

To reach "www.citibank.co.in" packet took  17 hops(routers).

The first column, the hop count, represents the number of stops your information has made along the route to attempt to contact the other computer. The next three columns are the round-trip times in milliseconds for three different attempts to reach the destination. The last column is the name of the host that responded to the request.

Hop 1 - - My wireless router IP.
Hop 2 - - My ISP(Airtel Broadband) local IP.
Hop 3 to 6 - My ISP(Airtel Broadband) IP.
Hop 17 - Citigroup IP.

You can also use pathping -n www.citibank.co.in

For better understanding of host details look into following sites
IP or Server Details.


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