What key concept is critical for troubleshooting failed login attempts via Active Directory?

The critical concept for troubleshooting failed login attempts via Active Directory is primarily centered around authentication source settings. This involves configuring how the firewall interfaces with Active Directory to authenticate users attempting to access the network.

When users attempt to log in, the firewall needs to correctly reference the Active Directory server's domain, credentials, and protocols used for authentication. If these settings are misconfigured—such as incorrect LDAP paths, wrong bind credentials, or issues with the synchronization of user accounts—failed login attempts may occur. Ensuring that authentication source settings are accurately set up will help in diagnosing and resolving issues related to user access and authentication failures.

Other areas such as session timeout configurations and firewall policy enforcement can influence user experience and access, but they do not directly address the initial point of authentication with Active Directory. Network interface settings are related to the physical or logical setup of connections and thus are not as relevant to resolving login failures tied specifically to authentication methods.