Network Traffic Analysis with Wireshark in GNS3

Sniffing and Evasion

Objective:

This training session aims to equip participants with the skills to integrate Wireshark into GNS3 for effective network traffic analysis. By the end of this session, attendees will be able to:

• Set up a basic network topology in GNS3.

• Capture and analyze packets using Wireshark within the GNS3 environment.

Prerequisites:

• GNS3 installed on your system.

• Wireshark installed and functioning properly.

Lab Setup:

Network Topology Configuration:

• Create a simple network in GNS3 comprising two routers, R1 and R2, connected via their FastEthernet interfaces.

• Assign the 10.0.0.1/30 to R1 (Fa0/0):

R1#configure terminal
R1(config)#interface fastEthernet 0/0
R1(config-if)#ip address 10.0.0.1 255.255.255.252
R1(config-if)#no shutdown

• Assign the 10.0.0.2/30 to R2 (Fa0/0):

R2#configure terminal
R2(config)#interface fastEthernet 0/0
R2(config-if)#ip add 10.0.0.2 255.255.255.252
R2(config-if)#no shutdown

• On R2, set a VTY password and an enable secret, both as "cisco".

R2(config)#line vty 0 4
R2(config-line)#password cisco
R2(config-line)#login
R2(config-line)#exit
R2(config)#enable secret cisco
R2(config)#^Z
R2#wr mem
Warning: Attempting to overwrite an NVRAM configuration previously written
by a different version of the system image.
Overwrite the previous NVRAM configuration?[confirm]
Building configuration...
[OK]

Packet Capture with Wireshark:

• In GNS3, right-click on the link between R1 and R2.

• Select "Start capture".

• Wireshark should launch automatically, displaying real-time packet capture.

Generating Traffic:

• Initiate a Telnet session from R1 to R2.

• Observe the packets in Wireshark corresponding to this session, including ARP, TCP, and Telnet packets.

Analyzing Captured Packets:

• In Wireshark, examine the details of the captured packets.

• For instance, inspect the TCP handshake packets to understand the encapsulation process: Ethernet frame → IP packet → TCP segment.

Keywords

Wireshark, GNS3, network analysis, packet capture, Cisco, Telnet, TCP handshake, ARP, IP addressing, router configuration, network simulation, cybersecurity, network troubleshooting, VTY password, enable secret, network security, protocol analysis, Ethernet frame, TCP segment, network monitoring , وایرشارک