Explaining how hardware and software control access to data in a network

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Quick Questions

Shade in the A or B circle for each question.

1. A student logs in to the school file server from a laptop. Which device first forwards the request towards the server?

A An antivirus program, which chooses the route for each packet

B A router, which uses its routing table to pick the next hop

2. Which is the best description of what a firewall does to a login request?

A It checks the password and decides which files the user may open

B It filters the request using rules, such as allow or deny by port or IP address

3. The server asks for a username and password. Which job is this?

A Authentication: proving who you are

B Authorisation: deciding what you may do

4. After login, Mia can read a Year 10 folder but cannot change it. What controls this?

A User permissions set by the operating system (read-only access)

B The network switch, which hides the files from her

5. Which step protects confidentiality while the login travels across a public network?

A Encryption with HTTPS or a VPN, so an eavesdropper only sees ciphertext

B Sending the password as plaintext so the server can read it faster

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1router -> firewall -> file server		ASoftware first proves who you are, then decides which files you may read or change.
2login(user, password) -> permissions check		BThe path a login request takes: the router moves it, the firewall filters it, and the server receives it.
3Encryption keeps data confidential while it travels, so anyone who intercepts it cannot read it.		CA switch only forwards data inside a LAN. It does not check passwords. The server's authentication software checks the password.
4A firewall rule can filter a request by port, so only expected traffic reaches the file server.		Dfirewall: allow port 445 from LAN, deny all
5Step 1: login \| Device: switch checks the password		EAllowing all traffic and denying none filters nothing, so unauthorised users can reach the data. Rules should allow only what is needed and deny the rest.
6firewall: allow all, then deny none \| Goal: confidentiality		FHTTPS: encrypt(data, key) -> ciphertext

Definitions

access control

Fill in the Blanks

Complete each line of code by filling in the missing parts.

1 switch: connects devices on the LAN 2 ______: forwards data to other networks 3 firewall: filters data by rules

1 user types username and password 2 server checks identity: ______________ 3 then it checks permissions

r = read, w = write, x = execute student permission: r-- student can only ____ the file

data in transit is encrypted with HTTPS eavesdroppers cannot read the data CIA goal kept: _______________

allow port 443 (HTTPS) allow port 445 (file server) default: ____ everything else

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A laptop SENDS login request

B router FORWARDS packets

C firewall ENCRYPTS the packets

D server CHECKS password hash

Question 2

A user ENTERS name and password

B HTTPS ENCRYPTS the login

C server COMPARES password hash

D IF match THEN DENY access

Question 3

A login OK: user is student

B AUTHENTICATE: check permission

C student may READ only

D write request is DENIED

Question 4

A encryption -> confidentiality

B hash check -> availability

C backup server -> availability

Question 5

A protocol <- HTTP

B port <- 443

C SEND login USING protocol

Answer Key

Explaining how hardware and software control access to data in a network

Section A: Quick Questions

B — A router, which uses its routing table to pick the next hop

B — It filters the request using rules, such as allow or deny by port or IP address

A — Authentication: proving who you are

A — User permissions set by the operating system (read-only access)

A — Encryption with HTTPS or a VPN, so an eavesdropper only sees ciphertext

Section B: Match the Pairs

router -> firewall -> file server → The path a login request takes: the router moves it, the firewall filters it, and the server receives it.

login(user, password) -> permissions check → Software first proves who you are, then decides which files you may read or change.

Encryption keeps data confidential while it travels, so anyone who intercepts it cannot read it. → HTTPS: encrypt(data, key) -> ciphertext

A firewall rule can filter a request by port, so only expected traffic reaches the file server. → firewall: allow port 445 from LAN, deny all

Step 1: login | Device: switch checks the password → A switch only forwards data inside a LAN. It does not check passwords. The server's authentication software checks the password.

firewall: allow all, then deny none | Goal: confidentiality → Allowing all traffic and denying none filters nothing, so unauthorised users can reach the data. Rules should allow only what is needed and deny the rest.

Section C: Definitions

access control — Hardware like routers and firewalls moves and filters a request; software like protocols, login, permissions and encryption decides who may see the data and keeps it safe.

Section D: Fill in the Blanks

1 switch: connects devices on the LAN
2 router: forwards data to other networks
3 firewall: filters data by rules

1 user types username and password
2 server checks identity: authentication
3 then it checks permissions

r = read, w = write, x = execute
student permission: r--
student can only read the file

data in transit is encrypted with HTTPS
eavesdroppers cannot read the data
CIA goal kept: confidentiality

allow port 443 (HTTPS)
allow port 445 (file server)
default: deny everything else

Section E: Spot the Error

C — A firewall filters traffic by its rules. It does not encrypt it. Encryption is done by protocols such as HTTPS. Line 3 should be: firewall FILTERS the packets.

D — If the hash matches, the user has proved who they are, so the server should allow access. Denying a correct login would harm availability. It should be: IF match THEN ALLOW access.

B — Authentication proves who you are, and the login already did that. Checking what the user may do is authorisation. It should be: AUTHORISE: check permission.

B — A hash check shows whether data was changed, so it protects integrity. Availability is about keeping the system working, for example with a backup server. It should be: hash check -> integrity.

A — Port 443 is used by HTTPS, which encrypts the login so others cannot read it (confidentiality). Plain HTTP sends data as readable text. It should be: protocol <- HTTPS.