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Finding Path of Packets

rounakpolley profile image Rounak Polley ・3 min read

We know data travels across the internet in small packets. But it does not fly from one computer to another computer instead it passes through various network devices. But, can we determine an approximate path through which the packets travel ?
The answer is yes!

For example the path of accessing www.facebook.com form Kolkata (India) looks like this.
(Note : Here I have joined server locations with straight lines for simplicity)
Reaching facebook.com from Kolkata

It can be done by using tracert command on Windows which is equivalent to traceroute command on Mac and Linux.
Note : These commands take some time to execute so be patient or to cancel mid-way press ctrl+c.

tracert or traceroute displays the route taken by packets from a local system to reach a remote server/host over an IP network (network that uses IP to send and receive messages between one or more computers).

tracert sends ICMP (Internet Control Message Protocol) echo packets to the destination and listens for the reply.
Trace route sets the TTL to 1 and increments it for every hop. The routers receiving the message decrement this value and when it reaches 0 they reply a message that the TTL has reached zero. This reply then tells client (which executed the command) from where it has returned. This process continues until the Destination is reached.

Following is a tracert on www.facebook.com. That I have used to plot the map shown above.

C:\Users\ROUNAK POLLEY>tracert www.facebook.com

Tracing route to star-mini.c10r.facebook.com [157.240.13.35]
over a maximum of 30 hops:

  1     2 ms     1 ms     1 ms  192.168.0.1
  2     4 ms     3 ms     3 ms  172.17.149.1
  3     7 ms    21 ms    13 ms  node-203-171-243-1.alliancebroadband.in [203.171.243.1]
  4     7 ms     7 ms     8 ms  192.168.199.109
  5     4 ms     4 ms     4 ms  node-203-171-240-1.alliancebroadband.in [203.171.240.1]
  6    42 ms    45 ms    46 ms  172.31.180.57
  7    42 ms    43 ms    42 ms  ix-ae-4-2.tcore1.CXR-Chennai.as6453.net [180.87.36.9]
  8    84 ms    77 ms    78 ms  if-ae-3-3.tcore2.CXR-Chennai.as6453.net [180.87.36.6]
  9    74 ms    75 ms    75 ms  if-ae-6-2.tcore2.SVW-Singapore.as6453.net [180.87.37.14]
 10    94 ms    81 ms    77 ms  180.87.15.246
 11    77 ms    78 ms    77 ms  po121.asw02.sin1.tfbnw.net [173.252.64.50]
 12    78 ms    77 ms    78 ms  po224.psw04.sin6.tfbnw.net [157.240.34.51]
 13    77 ms    76 ms    79 ms  157.240.36.117
 14    78 ms    76 ms    76 ms  edge-star-mini-shv-02-sin6.facebook.com [157.240.13.35]

Trace complete.

Output of the command :

  • The output is divided into columns which are

hop Number, RTT 1, RTT 2, RTT 3 Domain Name and IP Address
RTT stands for Round Trip Time.

  • Here 192.168.0.1 is the IP address of my router. And alliancebroadband.in is my ISP (Internet Service Provider) etc.
  • If a router does not respond within a timeout (TTL) then asterisk is printed. For example :
 3     *        *        *     Request timed out. 
 4     5 ms     *        *     node-203-171-243-1.alliancebroadband.in[203.171.243.1]
  • Generally when we use a IP location finder on the IP addresses returned by tracert we see that some of the IP(s) are private. This is due to the fact that these are the internal IP(s) of servers/gateways of some organizations.

'Hops' are nothing but the computers, routers, or any devices between the source and the destination.
For using different options with tracert type 'tracert' and press 'enter' (In the command prompt). It will show all the available syntax.

To visualize the physical locations we just use any IP Geolocation service like https://www.iplocation.net . And then simply plot them on the map.

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rounakpolley profile

Rounak Polley

@rounakpolley

Web Developer and Computer Science Engineer

Discussion

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Great content. Thanks for sharing. Just to add, if you want to visualize the IP location on Google maps, that tool
dnschecker.org/ip-location.php
with four geolocation databases information on IP, and displays each database information on Google maps, will surely help the user.