Windows authentication is a technology used by Windows-based operating systems to authenticate users and grant access to resources. It is used to validate a user's identity and grant them access to resources on the network, such as files, printers, and other network resources.
Windows authentication consists of two main components: Kerberos and NTLM. Kerberos is the primary authentication protocol used in Windows, and NTLM is used as a fallback in case Kerberos is not available.
Kerberos is an authentication protocol used by Windows-based systems to authenticate users and grant them access to resources. It is based on a ticket system, where a user is granted access to resources after they have been authenticated. The ticket is passed between the user, the resource they are trying to access, and the server. This process is known as ticket-granting.
NTLM is another authentication protocol used by Windows-based systems. It is used as a fallback if Kerberos is not available. NTLM does not use a ticket system like Kerberos, instead it performs a challenge-response authentication. This means that a user must provide a username and password, which is then checked against the user's credentials in the Active Directory. If the credentials are valid, then the user is granted access to the resource.
Windows also supports the use of passwords to authenticate users. This is done by sending the user's password to the server, which is then compared against the user's credentials stored in the Active Directory. If the passwords match, the user is granted access to the resource.
It is possible to authenticate users without a network connection using Windows authentication. This is done using cached credentials. When a user logs in to a Windows computer, the user's credentials are cached on the computer. When the user logs out, the credentials remain on the computer and can be used to authenticate the user when they try to access a resource. This allows users to access resources without a network connection.
Windows authentication is a secure way to authenticate users and grant them access to resources. It is based on a number of protocols, including Kerberos and NTLM, and can be used to authenticate users without a network connection using cached credentials.