2.1 - Infrastructure

2.1.1 Know and understand the purpose of data held in routing tables

Static Addresses

Static addresses are routes that are manually configured by a network administrator. They remain fixed in the routing table until they are manually changed or removed. Static routes are predictable and are often used in small or secure networks.

Dynamic Addresses

Dynamic addresses are learned automatically through routing protocols such as RIP, OSPF, or BGP. These routes update automatically when network conditions change, helping routers choose the most efficient path.

Network ID

The network ID identifies the destination network within the routing table. Routers use it to determine where data packets should be forwarded.

Subnet Mask

A subnet mask defines which portion of an IP address refers to the network and which portion refers to individual devices. It helps routers correctly match destinations.

Next Hop

The next hop is the IP address of the next router that a packet should be sent to on its journey to the destination network.

Interface (Device) Designation

This shows which physical or virtual interface on the router should be used to forward the packet, such as an Ethernet or wireless interface.

2.1.2 Be able to interpret data from routing tables

Interpreting Routing Table Data

Interpreting routing table data involves understanding how routers decide where to send network traffic. By examining network IDs, subnet masks, next hops, and interfaces, a network engineer can determine the path data packets will take and identify potential routing issues.

2.1.3 Know and understand the purpose of console applications that display TCP/IP network configurations

ipconfig / ifconfig

Console applications such as ipconfig (Windows) and ifconfig (Linux/macOS) are used to display TCP/IP network configuration details. These include IP addresses, subnet masks, default gateways, and network interface status.

2.1.4 Be able to interpret data from console applications

Interpreting Console Output

Interpreting console application output involves reading network information such as IP address configuration, connection status, and gateway information. This helps identify connectivity problems and verify correct network setup.

2.1.5 Know and understand the purpose of a firewall and its role in securing networks

Purpose of a Firewall

A firewall is a security device or software that monitors and controls incoming and outgoing network traffic. Its purpose is to protect networks from unauthorised access, malware, and other security threats.

2.1.6 Know and understand firewall security practices

Securing Firewall Administrator Access

Securing firewall administrator access ensures that only authorised users can modify firewall rules. This is achieved through strong passwords, role-based access control, and secure management interfaces.

Precedence Rules for ALLOW and BLOCK

Firewall precedence rules determine the order in which ALLOW and BLOCK rules are applied. Correct rule ordering is essential to ensure that security policies are enforced correctly and that critical traffic is not accidentally blocked.