The internet Flashcards
- Describe the role of an Internet Service provider (ISP):
Allows individuals and users to connect to the internet
- What is meant by the term protocol
A set of rules for communication between devices
- Define the internet:
a network of interconnected computer networks which use an end-to-end communication protocol. It is mostly wired with cables that pass under the ocean connecting different continents.
- What is the different between a router and a gateway?
A Router is used to connect different networks together and attempts to send packets via the fastest route possible which may be the route with the least number of hops or the least congested route at the time. A gateway is similar but it allows for networks that use different protocols to communicate by stripping the header of packets and replacing it with headers that comply with the protocols of the new network.
- How can a firewall act as a proxy server?
A firewall is a hardware/software that allows or stops individual packets from entering or leaving a network.
A proxy server is a server that sits between a private and a public network and monitors traffic between the two networks. A firewall acts as a proxy server if it manages the traffic between a public and a private network.
- Functions of a proxy server?
When a device in a private network sends a packet through a firewall and into a public network, the packet’s “sender” address is that of the firewall, rather than the device’s private IP address.
- Add web filtering features.
- Speeds up performance by caching websites.
- Describe how two devices can transmit data using asymmetric encryption?
Each device has a pair of mathematically related keys – a public key and a private key.
- A message encrypted using the public key can only be decrypted with the corresponding private key.
- A message is encrypted using the recipients public key this means the message can only be decrypted by the recipient’s private key which only they have access to.
- There is no need for private key to be shared -reduces risk of data breaches.
- Why may someone wish to use asymmetric encryption over symmetric encryption?
- In symmetric encryption the data is encrypted and decrypted using the same key which means the key should be shared over the network which makes is vulnerable to interceptions
- Define stateful inspection and how it works:
- Continuously monitors incoming and outgoing traffic and checks the payload of each packet instead of the just the header for suspicious activities. It requires the firewall to maintain a state table which keeps track of all the conversations to ensure all inbound and outbound packets are expected.
- Give vulnerabilities within a network and how to overcome them:
- Poor code quality for example code that leaves data left in memory to be exploited later. Code reviews help identify and remove vulnerabilities within programs. Firewalls can be used to monitor and identify suspicious traffic. Anti-virus software scans files and emails for suspicious activity.
- What is the difference between virus and worms?
A virus is a malicious form of self-replicating software that attaches itself to programs and files so it can easily infect the computer system. Worms unlike viruses don’t require a host program to spread instead copies itself independently through the network.
- How can a trojan cause harm?
It is malware that is disguised as useful software and when the program is run the malware is executed unknowing to the user doing malicious actions such as data theft, redirecting search requests, installing further malware etc.
- Describe how digital signatures work:
Used to verify that the message has not been tampered with during transmission.
- A digest is created using the message for example a number is generated by performing a hashing algorithm on the message so, if content of message is changed then digest won’t match that message.
- The digest is encrypted using sender’s private key and appended to the message,
- Then the whole message including the digest is encrypted using receivers’ public key.
- Once the message is received, the recipient can decrypt the overall message using their private key then decrypt the digest using the sender’s public key.
- The user performs the same hashing function on the message and checks if the digest matches. If it doesn’t match it can be assumed the message was altered during transmission.
- What is a digital certificate?
- Verifies ownership of a key pair to ensure a fake isn’t being used by an imposter. The certificate a serial number, the owner’s name, an expiry date, the owner’s public key and the certificate authority’s digital signature
- Describe the purpose of a Wireless Access Point:
- Wireless access point is usually wired and allows devices to connect to a wireless network and broadcast and receives wireless signals to and from devices on the network
- Describe the Purpose of Wireless network adapter
- Built into the device and allows devices to communicate using wi-fi.
- How does a MAC address whitelist work?
A MAC (media access control) address is a unique number that is assigned to a network interface card when the card is manufactured.
MAC address filtering is a method used to control which devices can connect to a network. IT specifies which device are allowed to connect to the network.
- Define baud rate, bit rate, bandwidth and latency and their relationships:
The bit rate is the number of bits transferred per second, the baud rate is the number of signal changes per second, bandwidth is the maximum rate of data transfer of a communication channel and latency is the delay from the time the signal is sent to the time it is received. The bit rate and the bandwidth are directly proportional. Bit rate = baud rate * number of bits per signal.
