Networking Flashcards
(26 cards)
What makes up a Network?
The internet is often described as “The information highway”
Media (Roads) :
Cabling that makes up our network
Traffic (Cars) :
Network traffic is the data that travels across a network
Devices (Junctions) :
Devices play a part on the network by either sending, receiving or directing network traffic
Protocols (Highway code) :
Due to the size of the network, it is important that there are rules in place to ensure communication is possible
What are the different types of Networks
PAN (Personal Area Network)
Used to connect personal devices
Example => Bluetooth between phone and headphones
LAN (Local Area Network)
Used to connect computers / devices in a single location like a home, office or school
Example => Wi-Fi network in your house
CAN (Campus Area Network)
Used for linking buildings within the same organization
Example => university with separated faculties network together
MAN (Metropolitan Area Network)
Used to connect LANs across a city / large area
Example => city wide government network
WAN (Wide Area Network)
Used for connecting LANs and MANs over long distances
Example => The Internet
What are some Network Devices
Client :
Almost always, the source or destination device of network traffic
Client devices include, PC’s, laptops, tablets, mobile phones, etc.
Described as having access to services from another device like a server
Servers :
Device on the network that “serves” other devices
Used as a central point of administration to implement permissions, forward traffic, data storage, etc.
Different purposes like Mail Server, Print Server and Web Server.
Switch :
Direct traffic within LANs to allow devices to communicate effectively
Separate collision domains per port to allow for easier and faster sharing data / resources on the network
Router :
2 purposes => Path Determination => Packet Forwarding
Forwarding packets between networks until packets reach the intended destination network
What is IP Addressing
The internet protocol address (IP) gives a numerical address that is assigned to each device that communicates over the IP address
IPv4 is the dominant variant of the IP that is used in the network, however due to running out of addresses IPv6 has been introduced to work in conjunction with IPv4.
What is the IPv4 Addressing
Address consists of 32 bits and are represented by the 4 octets separated by dot.
Value of each octet has a range of 0-255
Class determines how many hosts and networks are available on that network
Private IP addresses are local to the router and can only be used internally and are NOT routable
What are the Default Subnet Mask
Each IP address must have its own subnet mask
It allows networking devices to determine the network that the address belongs to
Made up with Hosts and Network
Subnets on classful addresses stay the same, which means that they cannot change the number of hosts in the network.
What is a Network Address
For network devices to determine the network that an address belongs to, they need to first determine the network address
A Network Address is a unique identifier assigned to a device on a computer network. It allows the device to communicate with other devices. In most cases, this refers to an IP address, such as 192.168.1.0, which identifies a device’s location within a network.
What is a Broadcast Address
Broadcast address is an address that, when used will send traffic to all the connected devices on that network
What are Classless IP Addressing
Due to the limitation of IPv4, the use of classful IP addressing is not ideal
To address this, we use private IP addressing as well as classless IP addressing or Classless Inter-Domain Routing (CIDR)
What are Network Media
For traffic to reach from source to destination, there needs to be a line of communication
Wired and Wireless
What are some Copper Media
Unshielded Twisted-Pairs (UTP) Cable - Most popular cable due to its lightness and ease of use. These cables are categorized
Shielded Twisted-Pair (STP) cables – used in difficult environments. It’s expensive and not easy to work with. These cables are categorized also
What are some Fiber Media Cable Design
Optical Fiber is a filament of very clear glass that can carry information in the form of light
This glass is a little thicker than a human hair
Fiber cabling is predominantly used on Wide Area Networks
What us Wireless Media
Wireless LAN’s or WLANs, use radio frequency (RF) technology to transmit and receive data over the air. This minimizes the need for wired connection.
WLANs give users mobility as they allow connection to a local area network without having to be physically connected by a cable.
What is the OSI Model
Establishes the standards for standards with regards to communication components
What is Layer 7: Application Layer and what Security risk does it have
Function: Provides network services directly to end-user applications.
Vulnerabilities:
- Cross-site scripting (XSS): Injecting malicious scripts into web pages.
- SQL injection: Manipulating database queries through input fields.
- Distributed Denial of Service (DDoS): Overwhelming services to disrupt access.
Mitigations:
- Implement input validation and output encoding.
- Use Web Application Firewalls (WAFs) to filter malicious traffic.
- Regularly update and patch applications to fix vulnerabilities
What is Layer 6: Presentation Layer and what Security risk does it have
Function: Translates data formats between applications and the network.
Vulnerabilities:
- Malformed data injection: Injecting malicious code through data formats.
- Content spoofing: Altering data presentation to deceive users.
Mitigations:
- Validate and sanitize all input data.
- Use secure libraries for data parsing and formatting.
- Implement strong encryption and decryption practices.
What is Layer 5: Session Layer and what Security risk does it have
Function: Manages sessions between applications.
Vulnerabilities:
- Session fixation: Forcing a user to use a known session ID.
- Session hijacking: Intercepting and taking over sessions.
Mitigations:
- Use unique session identifiers and regenerate them upon authentication.
- Implement session timeouts and re-authentication mechanisms.
What is Layer 4: Transport Layer and what Security risk does it have
Function: Provides end-to-end communication control.
Vulnerabilities:
- Port scanning: Identifying open ports for potential exploitation.
- Session hijacking: Taking over active sessions.
Mitigations:
- Use firewalls to block unauthorized ports.
- Employ secure protocols like TLS for data transmission.
- Implement session management techniques to detect anomalies.
What is Layer 3: Network Layer and what Security risk does it have
Function: Determines how data is sent to the receiving devices.
Vulnerabilities:
- IP spoofing: Falsifying IP addresses to masquerade as trusted sources.
- Routing attacks: Manipulating routing tables to redirect traffic.
Mitigations:
- Implement access control lists (ACLs) to filter traffic.
- Use secure routing protocols with authentication.
- Deploy intrusion detection and prevention systems (IDPS)
What is Layer 2: Data Link Layer and what Security risk does it have
Function: Ensures reliable data transfer between adjacent network nodes.
Vulnerabilities:
- MAC address spoofing: Impersonation of legitimate devices.
- MAC flooding: Overloading switch tables to intercept traffic.
- VLAN hopping: Gaining unauthorized access to different network segments.
Mitigations:
- Enable port security features on switches.
- Implement VLAN segmentation and proper configuration.
- Use 802.1X for network access control.
What is Layer 1: Physical Layer and what Security risk does it have
Function: Transmits raw bits over physical mediums like cables and wireless signals.
Vulnerabilities:
- Hardware tampering: Unauthorized physical access to network devices.
- Cable tapping: Interception of data through physical connections.
- Environmental threats: Damage from natural disasters or power outages.
Mitigations:
- Implement physical security measures (e.g., locks, surveillance).
- Use shielded cabling and secure cable routes.
- Employ environmental controls and uninterruptible power supplies (UPS).
What are Network Protocols
Network protocols are a set of rules that are used across networks to allow devices to have effective communication
What is the Transmission Control Protocol (TCP)
Connection orientated protocol, which means that before 2 devices can exchange data, a connection must be established
Reliable protocol as it carries out error checking and guarantees the delivery of data
What is the TCP 3 Way Handshake
Used to establish a connection
1: Client attempts to connect to a server and will send a signal to the server with the SYN flag
2: Server receives the SYN, it will respond with a SYN+ACK
3: Client will then acknowledge the server respond with an ACK
