Difficulty is at an intermediate level.
Graphical Network Simulator-3 (shortened to GNS3) is a network software emulator first released in 2008. It allows the combination of virtual and real devices, used to simulate complex networks. It uses Dynamips emulation software to simulate Cisco IOS.
GNS3 is used by many large companies including Exxon, Walmart, AT&T and NASA, and is also popular for preparation of network professional certification exams. As of 2015, the software has been downloaded 11 million times.
GNS3 or Graphical Network Simulator is a simulator used for virtual network designs, This software is an open source software and supports Cisco routers and switches by using an emulator known as dynamips. In this Video Tutorial you will learn to trace the route to various ports of the IOS devices. Traceroute command is used to identify the path followed by a packet to reach its destination. It gives us the path followed from source host to destination host and also helps to know if the path is reachable or not. Traceroute therefore can be used to troubleshoot the network as it tells us about the path failures if there are any with the help of characters where each character has its own assigned meaning. To be able to use it you will have to follow the steps given below.
The Step one will be to design a network so that the user can trace the paths which form the network. In the video tutorial I have used four routers R1, R2, R3, R4 which are connected to four switches and these switches are connected to hosts. To be able to start the traceroute you will have to assign IP addresses to the ports of the four routers which are connected in the network. So, the next step will be to start the IP addressing. Here I will upload an image to help you get idea of the network.
Step two as explained above will be to do the IP addressing of the ports which are connected to each other in the network. So first we will look into Router 1, You will look for the port which is connected to the Router 2, Here port fastethernet 0/0 is connected to R2. You will have to configure it. The configuration for the fastethernet 0/0 in this network is shown below.
interface fastethernet 0/0
ip address 10.0.1.1 255.255.255.0
no shutdown
exit
do wr
The configuration is also shown with an image below.
interface fastethernet 0/0
ip address 10.0.1.2 255.255.255.0
no shutdown
exit
interface fastethernet 0/1
ip address 10.0.2.1 255.255.255.0
no shutdown
exit
do wr
This configuration is also shown with an image to relate to the video tutorial.
interface fastethernet 0/0
ip address 10.0.2.2 255.255.255.0
no shutdown
exit
interface fastethernet 0/1
ip address 10.0.3.1 255.255.255.0
exit
do wr
This configuration is also shown with an image.
interface fastethernet 0/0
ip address 10.0.3.2 255.255.255.0
no shutdown
exit
do wr
The configuration is also shown below.
The final step will be to use the traceroute command, In the Video you will find that i have tried to trace the route to IP address 10.0.2.2 from the Router 2, i.e I have used the command from R2 to start tracing the route to 10.0.2.2 address and the command for that will be shown below. Remember the command is used in the privilge mode only.
R2#traceroute 10.0.2.2
This is also shown with an image
Similarly I have traced route using the R1, I have traced the address 10.0.1.2 which can be shown as below.
R1#traceroute 10.0.1.2
The route is shown is as functional, lets suppose the address 10.0.2.2 fails to respond to the traceroute call from router 1, the configuration for this will be shown below.
R1#traceroute 10.0.2.2
This IP is not able to respond and the output of traceroute is in the form of different characters, here in the video its in the form of ' * ' . The network problem shown by this ' * ' is that the probe has timed out. This can be shown with an image below.
Many other characters may be displayed, I will provide you the list of characters which represent problems of the network. These help to define the problems of the network and help to troubleshoot the network.
'*' - the probe has timed out.
A - administratively prohibited (e.g, with an access-list).
Q - source quench (the destination is busy).
I - user interrupted test.
U - port is unreachable.
N - the network is unreachable.
P - the protocol is unreachable.
T - timeout.
? - unknown packet type.
Learn networking with the help of gns3 simulator. Follow the tutorial.
GNS3- Basic Router Configuration (Part 1)
GNS3- Basic Router Configuration (Part 2)
GNS3- Basic Router Configuration (Part 3)
GNS3- Basic Router Configuration (Part 4)
GNS3- Basic Router Configuration (Part 5)
GNS3- Basic Router Configuration (Part 6)
GNS3- Basic Router Configuration (Part 7)
GNS3- Basic Router Configuration (Part 8)