A routing table is used in computer networking to store information needed to make routing decisions. It is a data structure that contains information about paths to different network destinations, and it works as an instruction guide for networks.
When different data packets (pieces of information) are sent out to a network over the Internet, routing tables are used to determine which route the information should take in order to reach its destination most efficiently. This is done by using various algorithms to calculate the most effective way for data to be moved from one point to another.
Typically, a routing table contains information concerning destination addresses, network interfaces, and other criteria. It also contains entries for each of the permanent routes that have been set up on the network. When a network device with routing capabilities is introduced into the network, it will usually adopt the existing routing table.
Routing tables can also be used for security purposes. If someone wants to restrict access to the network and prevent specific types of traffic from entering, a routing table can be used to ensure that only authorized traffic reaches the destination. By blocking specific IP addresses or filtering out certain protocols, a routing table can be used to configure security policies to protect the privacy and integrity of data.
Routing tables are used in traditional IP networking, as well as in protocols such as the Multi Protocol Label Switching (MPLS) technology to provide connectivity for Virtual Private Networks (VPN) and other advanced networking services. Despite being an integral part of network infrastructure, the complexity of routing tables means that most users do not need to configure them manually.
