RADIUS servers make use of the protocol in the UDP transport layer on port 1812 to establish connections between teams to authenticate. When we configure a RADIUS server, we can define whether we want it to use TCP or UDP, and we can also define the port to use, although by default it is always UDP 1812. RADIUS servers are widely used by Internet operators (PPPoE), but they are also widely used in the WiFi networks of hotels, universities or anywhere we want to provide additional security to the wireless network, it can also be used to authenticate to clients that make use of the 802.1X protocol for Ethernet, and it could even be used to authenticate the VPN clients that we want, in this way, we will have all the centralized authentication in a single point in an easy and simple way, without having to have several databases with different data. RADIUS ( Remote Access Dial In User Service ) is a protocol that stands out for offering a security mechanism, flexibility, expandability, and simplified management of access credentials to a network resource. It is an authentication and authorization protocol For access to the network, this protocol uses a client-server scheme, that is, a user with credentials to access the resource connects against a server that will be in charge of verifying the authenticity of the information, and will be the in charge of determining whether or not the user accesses the shared resource. Thanks to the use of RADIUS servers, the network administrator can control at all times the beginning and end of the authentication and authorization period of the clients, for example, we can easily expel a user who has previously logged in for whatever reason. What is FreeRADIUS and why is it related to RADIUS servers? What is a RADIUS server and what is it for?.
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What is a RADIUS server and what is it for?.