What is the default blacklisting interval for an extension after exceeding authentication attempts?

The correct answer, which indicates the default blacklisting interval for an extension after exceeding the number of allowed authentication attempts, is based on a time frame set to manage potential security risks associated with repeated unauthorized access attempts. The default setting is typically designed to deter brute-force attacks and protect user accounts.

When an extension surpasses the specified limit for authentication attempts, it is temporarily blacklisted, meaning that further attempts to log in are blocked for a designated time. The standard practice in such configurations is to enforce a 1800-second blacklist, translating to a 30-minute lockout period. This provides sufficient time for the potential threat to pass while allowing legitimate users to regain access after a reasonable delay.

It's notable that the other options present durations that either exceed or are reflective of misspecified intervals. For instance, 1800 minutes would amount to an impractical and excessively long lockout duration, whereas the other time frames like 300 minutes or 60 minutes do not align with common security practices regarding temporary account lockouts in telephony systems, such as those used in 3CX setups. This understanding of the default blacklisting interval allows users to better grasp the security measures in place to safeguard their communications.