CTP-Services-01: DHCP Analysis

Scenario

An unknown device was connected to the corporate network without authorisation. The network admin captured traffic at that exact moment.

Analyze the capture and answer the questions.

Capture

Download the provided PCAP file and analyze the traffic using Wireshark.

Download CTP-Services-01 PCAP File

Tasks

Task 1 What is the MAC address of the DHCP client?
Task 2 What IP address is offered to the client?
Task 3 What IP address is finally assigned to the client?
Task 4 What is the IP address of the DHCP server?
Task 5 What subnet mask is assigned?
Task 6 What default gateway is provided?
Task 7 What DNS server(s) are configured?
View Expert Analysis
Task 1

Client MAC address is 00:e0:fc:fc:41:dc

You can find it in packet #1

Task 2

The IP address 192.168.1.254 is being offered.

It can be found in packet #2 (DHCP Offer) in the field "Your (client) IP address".

Task 3

The IP address 192.168.1.254 is assigned because only one IP address was offered.

The client requests the IP address in packet #3 (DHCP Request) as DHCP option 50.

Task 4

The IP address of the DHCP server is 192.168.1.1.

It can be found, among other places, in packet #3 (DHCP Request) as DHCP option 54.

Task 5

The subnet 255.255.255.0 is assigned.

It can be found in packet #2 as DHCP option 1.

Task 6

The client is assigned the gateway 192.168.1.1.

It can be found in packet #3 as DHCP option 3.

Task 7

The client is assigned the DNS server of 9.9.9.9.

It can be found in packet #3 as DHCP option 6.

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