Bug Bounty Hunting — Complete Guide (Part-10)

Network infrastructure

Your network relies on various standard-compliant devices to function. The number of these devices used depends on the network’s size, with multiple devices often forming its backbone.

Repeater

A repeater is a device with two ports designed to repeat network signals. It is used when network devices are spaced apart. The repeater operates by regenerating data packets at their original strength without modifying or interpreting them, and it does not amplify the signal.

Bridge

A bridge segments a network and selectively forwards data packets between these segments based on MAC addresses. It helps optimize network performance by minimizing unnecessary traffic within segments.

Hub

A hub functions as a multiport repeater in a network, facilitating the connection of multiple devices and shaping the network layout. Hubs can be cascaded to create network branches or used as endpoints to form star topologies with various user devices. They feature multiple ports that serve as input/output Ethernet connections between the hub and network devices. Hubs operate at the speed of the slowest device on the network and do not interpret or filter data packets; instead, they broadcast copies of each packet to all connected devices.

Types of hubs

This hub is designed for 100-Mbps networks and is available in Class I and Class II types. The main distinction between them lies in their data transmission delay. A Class I hub introduces a signal delay of up to 140-bit times, whereas a Class II hub has a delay of up to 96-bit times. This delay enables the translation of data between different base types. However, in a hub-based network, only two Class II hubs can be utilized due to their higher speed, which increases the probability of packet collisions.

In traditional hub networks, the speed of the entire network is limited by the slowest connected device. For instance, if there are both 10-Mbps and 100-Mbps devices on the network, the network operates at 10 Mbps overall. Dual-speed hubs address this issue by acting as a bridge between devices of different speeds.

Hubs are typically used for small, ad-hoc networks with a few devices. However, they are seldom used at an enterprise level due to their limitations in managing network traffic and optimizing performance compared to more sophisticated network devices like switches and routers.

Switch

A switch integrates the capabilities of both a bridge and a hub. It segments networks and has the ability to interpret and filter packet data, directing it specifically to the intended network device. Switches utilize the MAC addresses of network devices to determine the destination of data packets. Unlike hubs, switches operate in full-duplex mode, enabling simultaneous transmission and reception of data between the switch and network devices, which enhances network efficiency and performance.

Features

Modern Ethernet switches indeed provide significantly enhanced functionality compared to Ethernet hubs.

Ethernet switches can adjust the speed of inbound packets to match the connection speed of the destination network. This dynamic adjustment helps optimize network performance and efficiency.

Many modern switches support PoE, which allows network devices such as VoIP phones, wireless access points, and IP cameras to receive power directly from the switch through the Ethernet cable. This eliminates the need for separate power supplies, simplifying installation and maintenance.

Additional modules and features

Ethernet switches can accommodate various modules to extend their functionality. These modules can enable features such as:

This feature duplicates traffic from one port on a switch to another port for monitoring purposes, which is useful for network troubleshooting and analysis.

Specialized modules can capture and analyze network traffic in real-time, aiding in network diagnostics and security monitoring.

Some switches can integrate with IDS modules to detect and prevent unauthorized access and malicious activities within the network.

Overall, Ethernet switches provide robust capabilities for managing and optimizing network traffic, supporting diverse network applications, and enhancing network security and performance. These features make them essential components in modern network infrastructures, particularly in enterprise and business environments.

Types of Ethernet switches

There are two main types of switches: unmanaged and managed.

Unmanaged switches are basic and do not allow for customization. They are typically used in small office or home setups where packet switching happens automatically.

On the other hand, managed switches provide extensive configuration options. They allow adjustment of settings, behaviors, and operations through interfaces like command-line (CLI) via Telnet or Secure Shell (SSH), Remote Console, or web-based interfaces.

Managed switches commonly offer several configuration options:

Manages LAN traffic to prioritize critical systems such as voice-data packets, ensuring timely delivery.

Creates separate logical groups of devices within the network. Traffic in one VLAN remains isolated from others, enhancing network security and performance.

Establishes alternate paths in the network to maintain connectivity in case of cable or device failures, ensuring network resilience.

Duplicates network traffic from multiple ports to a single port, aiding network analysis and troubleshooting.

Allows control over the bandwidth usage of specific ports, enabling the allocation of higher bandwidth to critical applications like databases or VoIP and lower bandwidth for less critical applications like email.

Controls which devices can access the network through the switch, enhancing network security by allowing only authorized devices.

Configures Simple Network Management Protocol (SNMP) for network monitoring tools, facilitating network management and performance monitoring.

Managed switches are further categorized into two subtypes:

These offer a simplified management interface, typically through a web-based platform. They support VLANs, port mirroring, and bandwidth control.

These provide full-fledged management capabilities through CLI, remote console, or web interfaces, offering all the aforementioned configuration options.

In summary, while unmanaged switches are straightforward and require no configuration, managed switches offer extensive customization options that are crucial for larger networks and enterprise environments.

Routers

A router serves to connect networks with differing IP address ranges. It processes and directs data packets to their correct destinations, utilizing IP address information. Routers can also manage network traffic issues by rerouting data around problems. They are commonly referred to as gateways and are configured with a default gateway IP address when setting up network devices.

In interconnected networks, routers maintain routing tables that specify the optimal paths between networks. Acting as the authority for network devices on their networks, routers share routing information using protocols like the Border Gateway Protocol (BGP).

There are various types of routers tailored to different network requirements:

These economical devices are used in small offices or homes, primarily for basic routing needs.

These routers aggregate routing data from multiple sources. They feature enhanced memory and processing capabilities to handle extensive routing information and manage quality of service (QoS) across wide-area networks (WANs).

Positioned at the boundary between internal networks and external networks (e.g., the internet), edge routers filter and route traffic based on packet headers. They often include security features such as firewalls and may handle DHCP and DNS services.

Also known as enterprise routers, these high-bandwidth devices connect large-scale networks across different locations or buildings. Core routers prioritize packet forwarding efficiency to minimize congestion and packet loss, often forwarding traffic to edge routers.

These devices combine the functions of access routers with wireless access points, allowing wireless connectivity within a network. They enable the creation of wireless local area networks (LANs) and manage access to external networks through edge routers.

It’s important to note that a wireless modem, provided by ISPs for home or office use, converts ISP signals into usable network signals for computers. Wireless modems often integrate routing functions to enable private network creation, distinct from wireless routers that focus on both routing and wireless connectivity within LANs.