The Ultimate Guide To Network Switch Router And Firewall

1. Router

Router: A computer network device that forwards the received data packets according to the destination IP address and selects the appropriate transmission path until it is forwarded to the destination. This process is called routing.

It works in the third network layer of the OSI (Open System Interconnection) model and is the main node device of the Internet.

The router finds the best transmission path during the data transmission process and effectively transmits the data to the destination site. Simply put, it is like a transit station for express delivery, sorting express delivery according to different delivery addresses, and thus finding the fastest delivery route for each express delivery.

2. Switch

Switch: Realize communication within the local area network. For example, colleagues in the company want to transfer important files and do not want to cause file information leakage through the transmission of other software. At this time, they can connect their two computers to the switch and transmit data through the MAC table on the switch. At this time, the transmission is only forwarded on the switch within the company, without the intervention of a third party, which is not only fast but also safe.

The switch can be directly connected to the user terminal computer, or it can be connected to the wireless AP device to connect the mobile phone to WIFI Internet access, and it can also be connected to the optical fiber device.

Common switches in life are access switches that work at the second layer of the OSI model, the data link layer.

It "learns" to match the MAC address of each port connected to the corresponding port and store it in the MAC address table in the switch cache. The data frame is sent to the destination through this MAC table.

3. Firewall

A firewall is not a physical wall in life. It is actually a security isolation technology built between the internal network and the external public network, providing a security barrier for internal and external network communications. It is usually divided into three areas: trusted (intranet) area, untrusted (extranet) area, and DMZ area.

Four functions of the firewall:

Intrusion detection: It can perform security checks when the external network accesses the internal network, and even detect and block dangerous operations, which greatly guarantees the security of the network, just like the common security checks in life;

Network address translation: IP address conversion between the internal network and the external network, such as Chinese and English cannot communicate directly, and they need to be converted to each other for communication.

Strengthen network security strategy: realize centralized security management, and monitor and restrict network information security during information access, such as company access control, prohibiting illegal company personnel from entering;

Monitor and audit network operations: record system management operations and security information, and provide data tracking for network management, such as community monitoring.