Wireshark/IPv4 remote

Wireshark is a free and open source packet analyzer used for network troubleshooting and analysis. These activities will show you how to use Wireshark to capture and analyze remote IPv4 traffic.

Readings

• Wikipedia: IPv4

Preparation

To prepare for this activity:

1. Start Windows.
2. Log in if necessary.
3. Install Wireshark.

Activity 1 - Capture Remote IPv4 Traffic

To capture remote IPv4 traffic:

1. Start a Wireshark capture.
2. Use ping 8.8.8.8 to ping an Internet host by IP address.
3. Stop the Wireshark capture.

Activity 2 - Analyze Remote IPv4 Outbound Traffic

To analyze remote IPv4 outbound traffic:

1. Observe the traffic captured in the top Wireshark packet list pane. Look for traffic with ICMP listed as the protocol. To view only ICMP traffic, type icmp (lower case) in the Filter box and press Enter.
2. Select the first ICMP packet, labeled Echo (ping) request.
3. Observe the packet details in the middle Wireshark packet details pane. Notice that it is an Ethernet II / Internet Protocol Version 4 / Internet Control Message Protocol frame.
4. Expand Ethernet II to view Ethernet details.
5. Observe the Destination field. This should contain the MAC address of your default gateway. You can use arp -a to confirm. Notice that remote Internet layer traffic is processed as local Link layer traffic. The default gateway will route the packet to the Internet.
6. Observe the Source field. This should contain your MAC address. You can use ipconfig /all or getmac to confirm.
7. Observe the Type field. Notice that the type is 0x0800, indicating IP.
8. Expand Internet Protocol Version 4 to view IP details.
9. Observe the Source address. Notice that the source address is your IP address.
10. Observe the Destination address. Notice that the destination address is the Internet host IP address.

Activity 3 - Analyze Remote IPv4 Inbound Traffic

To analyze remote IPv4 inbound traffic:

1. In the top Wireshark packet list pane, select the second ICMP packet, labeled Echo (ping) reply.
2. Observe the packet details in the middle Wireshark packet details pane. Notice that it is an Ethernet II / Internet Protocol Version 4 / Internet Control Message Protocol frame.
3. Expand Ethernet II to view Ethernet details.
4. Observe the Destination field. This should contain your MAC address.
5. Observe the Source field. This should contain the MAC address of your default gateway. Notice that the remote Internet layer traffic is returned as local Link layer traffic. The routers between the Internet host and your network routed the packet back to your router so that it could forward the packet back to your computer.
6. Observe the Type field. Notice that the type is 0x0800, indicating IP.
7. Expand Internet Protocol Version 4 to view IP details.
8. Observe the Source address. Notice that the source address is the Internet host IP address.
9. Observe the Destination address. Notice that the destination address is your IP address.
10. Close Wireshark to complete this activity. Quit without Saving to discard the captured traffic.

References

• Wireshark: User's Guide
• Wireshark: IPv4