FIT9137
Semester 1 2025
Assignment 3 Specification

Submission Guidelines:
● Deadline: Semester-1 Week-14 Tuesday 2025 [10th June 2025 11:55 PM]
● You need to submit
▪ a report (a PDF file including your screenshots with file name format as
FirstName_STUDENT_ID.pdf), and
▪ your network configuration file (the CORE file name format as
FirstName_STUDENT_ID.imn) containing the required changes to complete the
assignment tasks.
● Both files must be submitted via Moodle under a single submission link.
● Do not submit a compression of multiple files. Such submissions may receive a mark of
zero.
● A handwritten document is not acceptable and will not be marked even if converted and
submitted electronically.
● It is the student's responsibility to make sure that the submitted files can be opened on a
standard computer (without requiring specialised software), and that all contents such as
images and texts shown are understandable/readable (in English). After uploading the files
as draft (before finalising the submission), we recommend you download your
submitted files and check that they open and run properly. If the files
are not readable, openable, or corrupted, then you may receive a mark
of zero. Once you finalise your submission, you will not be able to revise it.
● Assignment files left in draft mode are not accepted and will not be marked. Make sure to
finalise your submission by the deadline.
● Written texts in your PDF must be submitted as actual texts, and not an image of a text.
Accordingly, screenshots of typed texts as images are not accepted (of course, this rule
excludes the screenshots you take to show the computer’s display).
● For the CORE configuration file, you may see a warning/error message returned by Turnitin
after you upload your files. That is completely fine and you can simply ignore the Turnitin
warning/error message for the IMN file.
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● All special consideration/extension requests must be submitted via
https://www.monash.edu/students/admin/assessments/cant-complete

Marks: This assignment is marked out of 100 marks, and it is worth 45% of your UNIT total marks. You
must submit both the CORE configuration file and the PDF report. If you submit only one of the files, you
will receive a mark of zero.
Feedback: Your Tutor will provide you with marks and feedback (if your submitted PDF file and the
CORE *.imn file are readable and markable)
Brief Description
Assignment will include the materials covered within Weeks 6-12. In particular, the assignment will
consist of questions related to network and transport layers, structures and functions of local area,
backbone and wide area networks, and network security. The format of the student submission will
be a written report and a network configuration.
Learning Outcomes covered
This Assignment covers material from Weeks 6-12. This is an individual assignment. By completing
this Assignment, you will understand the learning outcomes 4 to 7.
• Examine networks using the underlying fundamental theories, models and protocols for data
transmission.
• Analyse and formulate the functions and architectures of (wireless) local area networks, wide
area networks and the Internet.
• Identify cybersecurity threats and ethical considerations on the Internet.
• Apply and implement cybersecurity enabling techniques and countermeasures such as virtual
private networks (VPN).
Academic Integrity
This is an individual assignment and group work is prohibited. It is an academic integrity
requirement that your submitted work be original. Penalties will be applied to the whole submission
if there is any evidence of copying, collaboration, pasting from websites, or copying from textbooks.
When asked to use the Internet, books, or other academic resources to answer a question, it does not
mean to copy the text verbatim from the source. You must write the answers in your own words such
that your understanding of the answer is evident. You must always cite your references within the
text and list them at the end of the report. Academic integrity policies apply to all assessments. You
can refer to this link below:
https://www.monash.edu/student-academic-success/learnhq/maintain-academic-integrity

Penalties
Late submissions will result in a 5% deduction of the total marks per calendar day (up to 7 days). For
example, if you get 80/100 marks originally and submit 2 days late, then you would get a 10-mark
penalty (5 marks/day) and your final marks would be 70/100. Note that the total number of late
submission days is calculated by rounding up, e.g., if a submission is strictly more than 5 days (and at
most 6 days) late, then a 6-day penalty would be applied. Submissions more than 7 calendar days
late will receive a mark of zero (0) and no assessment feedback will be provided.
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Network Configuration and Security
Introduction
For this assignment you will use the core network emulator to complete a series of tasks on an
individual core configuration file that is generated for you. To download your individual core
configuration file, open the unit’s Moodle page then navigate to the Assessments section and follow
the provided instructions for Assignment 3 to downloaded the *.imn file for you to use.
You must write a report to explain
- the changes you make,
- the configurations you add to achieve the goals of each task,
- your reasons for each change/configuration, and
- the tests you perform to check the task is accomplished.

Your submitted core file will be marked by running the configuration and testing that the tasks are
completed. The report will serve as a reference to be checked during marking. However, if a test fails
when running your submitted core file, you will receive no mark for that failed test (i.e., part of a task)
regardless of your explanations in the report. If tasks are similar, you only need to explain your reasons
once, and then just report the changes you make to individual services on each node.

Network Structure
The provided network is composed of two organisations labelled Talos and Delos, a router named
Internet playing the role of the Internet, and a global DNS server named clio. The internal
subnets of talos are labelled Internal, and the public servers of the talos network are placed in a
separate subnet named DMZ. The Internet facing router of the Talos organisation, R3, is also its
network firewall. The Delos network is divided into two subnets: (i) a subnet for the organisation clients
and private servers and (ii) a subnet for its public servers. The public servers of Delos are named
apollo, artemis, and demeter providing web, domain name, and mail services respectively.

DNS Setup
The core file is configured to resolve the domain names between the two organisations, talos.edu
and delos.edu. This is achieved through a global DNS server named clio. The server only resolves
the names for the two domains in the configuration ( talos.edu and delos.edu) by sending the
request to the corresponding nameserver for each domain and sending back the response to the
requesting client. Each DNS server in aforementioned networks must have access to UDP port 53 of
the server clio as the organisation DNS servers resolve the names on behalf of their respective
clients. You do not need to make any changes to DNS servers; this section only explains the DNS
setup.
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Important Notes
• It is recommended to use tcpdump if you wish to capture traffic and to observe whether the
packets reach their intended destination when trying to accomplish the tasks. To use tcpdump,
you can right click on a node and move the mouse to select tcpdump in the provided list and then
select the intended interface. You can also run tcpdump from the command line using the
command tcpdump -l - i eth0 to print the summary of the captured packets from the eth0
interface in the terminal. To write the captured packets to a file, use the command with w option
followed by a filename. For instance, running the command tcpdump -w
/home/muni/R3_eth3.pcap - i eth3 on the node R3 will capture the traffic on its eth3
interface and store the frames in a file named R3_eth3.pcap under /home/muni directory.
You can then stop the capture with Control+C and use Wireshark to analyse the captured
packets.
• Any changes you make to the nodes when the emulation is running will be lost when you stop the
emulation. You can test the changes you want to make when the emulation is running and once
you have the correct commands, then add them through the GUI in the proper service. For
example, to add static routes to a router that persist and will be stored with the configuration file,
you need to add ip route add commands to the StaticRoute service of that router.
• If you make changes to a core configuration file and then close the CORE window without saving
the changes, you will not be warned, and the changes will be lost. Hence if you wish to keep the
changes you have made, you must save these changes before closing the CORE window.
Please note: changes are to be saved for static routing, DHCP configuration & Firewall
configurations.
• Make sure to keep a backup of your CORE file somewhere outside of the VM in case you
encounter issues with your VM, and you need to replace the VM. This will make sure that you
would not lose the work you have done. It is your responsibility to back up your work.
• In the provided configuration file, you must NOT alter the overall network structure or topology,
including device and node names or IP addresses, nor can you add or remove nodes.
Additionally, you are NOT allowed to modify link speeds or link delays, and implementing any
extra network services such as VLAN, VPN, or NAT is prohibited. If you do not obey these rules,
your submitted work will be deemed invalid and will receive a zero mark.

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Tasks
Task A: Routing [35 + 10 = 45 Marks]
The routing tables of the routers in the provided network are NOT configured. The correct
configuration of this task allows any host from any network to reach any other host in the entire
network. You must satisfy the following requirements while completing static routing task:

1. All routers must be configured solely with a static routing table; dynamic routing is NOT allowed.
Static routing should be set up using the given link delays (which include all of processing,
transmission and propagation delays) specified in the provided configuration file. You don’t need
to consider the link speed for this part.
2. All hosts inside the talos.edu network must be reachable from any other host within that
network through an optimal path. You need to add static routes to routers R1, R2, R3, and R4 to
accomplish this goal. You must explain your reasons for choosing a path in the report. The
notation us for links represents the propagation delay in microseconds. You can assume that
the processing and transmission delays at the routers are negligible.
3. The router R3 must be the default gateway of the talos.edu network. The router Internet
must be the default gateway of R3 and minerva (the only router of Delos). You will lose marks
if you create routing loops.

Task B: DHCP Server [8 + 2 = 10 Marks]
The clients of delos are configured with static IP addresses. Your task is to:
1. Configure DHCP server on the node minerva to assign dynamic IP addresses and other
required settings to the client machines in the client’s subnet.
2. You can make use of the DHCP server configuration on R1 as a reference to follow.
3. Enable DHCP client service on clients of delos.
Note: The node leto is a private local server in the client’s subnet and must have a static IP
address as assigned for the given configuration.

Task C: Firewall [45 Marks]
The node R3 is the firewall for talos network. Configure the Firewall service on this node to satisfy
the following requirements:
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1. Allow traffic from anywhere to DMZ for the provided service by each server. This must be limited
to only the public service(s) that a server provides: dns only DNS, web only HTTP, mail only
SMTP. [9 Marks]
2. Allow servers in DMZ to initiate a communication if it is required by the service the server
provides and only for that service (stateful inspection: DMZ → External). [6 Marks]
3. Allow internal hosts to access all services provided by servers in the DMZ (stateful inspection:
Internal → DMZ). This includes all services that DMZ servers provide. You can be more
permissive here and use address ranges and all IP traffic. All servers in DMZ run SSH service
which you can use to test your rules for the internal subnets. [6 Marks]
4. Allow internal hosts to reach other internal hosts (this is only if the internal traffic passes through
R3). All traffic is allowed if it is internal to internal communication. [3 Marks]
5. Allow internal nodes to access external servers however packets from external to internal are
only allowed if they are responses to communications that were initiated from inside (stateful
inspection: Internal → External). [9 Marks]
6. Allow only the nodes in clients subnet of talos to ssh to node R3 (any host connected to the
R1.eth0 subnet). [4 Marks]
7. Permit node R3 to send ICMP echo request messages to internal talos nodes and all DMZ
servers and receive ICMP echo replies from those nodes and servers. Also, permit internal talos
nodes and all DMZ servers to send ICMP echo request messages to node R3 and receive ICMP
echo reply from the node R3. [8 Marks]
8. All other traffic must be dropped (see Notes below).

Important Notes for Task C:
• If the Requirement 8 is not satisfied, you will receive a zero mark for the firewall task regardless
of any other correct rule you add as it would expose the entire network. You will lose partial
marks if your rules are too permissive allowing more traffic than specified to reach the destination
for each requirement.
• You only receive marks if the test for each requirement succeeds. No partial marks will be given if
only part of a rule is correct. When two rules are required for the incoming and outgoing traffic, no
partial marks will be given if one of the rules is correct.
• For stateful inspection, the traffic is allowed if it is initiated from the more trusted side of the
firewall to the less trusted side. The traffic in the opposite direction, from the less trusted interface
to the more trusted interface, is only allowed if the packets are the responses to an initiated
communication from the more trusted side. The trust level in the requirements is indicated as
Higher→ Lower for each stateful inspection, meaning the connection initiation is allowed from the
higher level to the lower level and only the responses for the initiated connections are allowed
from the lower level to the higher level.
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• If you have reachability issues in Task A, i.e. a host is not reachable from another host, you may
lose marks in firewall tests as well when the traffic must be allowed. You will not lose any marks
for firewall rules if a host is reachable but through a sub-optimal path and the firewall rules are
correct.
• You must submit the CORE file with Firewall service enabled on node R3. The Firewall service is
enabled in the individual files without any rules hence all traffic is allowed.
Reference Notes
Please acknowledge any reference appropriately and the use of any AI tools (refer to the
assignment link on Moodle to access information from Learn HQ).
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学霸联盟