A company's wireless network uses MAC address filtering, encryption and a firewall.
(a) Explain how MAC address filtering helps to keep the network secure. [2]
(b) Explain how encryption protects data sent across the network. [2]
(c) Describe the purpose of a firewall. [1]
- (a) The router / wireless access point checks the MAC address (the unique physical address of a device's network interface card) of each device trying to connect against a list of allowed addresses; allow against a list of blocked addresses(1)
- (a) Only devices whose address is on the allowed list can connect / devices not on the list (or on the blocked list) are refused, so unauthorised devices cannot join the network(1)
- (b) Data is encoded / scrambled (into ciphertext) using an algorithm and a key(1)
- (b) So if it is intercepted it cannot be understood / read without the (decryption) key; do not accept 'stops data being intercepted / stolen'(1)
- (c) Monitors incoming and outgoing network traffic and allows or blocks specific traffic based on a set of (security) rules; allow prevents unauthorised access to the network from outside(1)
- Answer: (a) The router checks each device's MAC address against an allowed list, so unknown devices cannot connect. (b) Data is scrambled using a key, so intercepted data cannot be understood without the key. (c) A firewall monitors incoming/outgoing traffic and blocks traffic that breaks its rules.
- Examiner tip: Encryption does NOT stop interception – it stops intercepted data being understood.