Which of the following is the default authentication mode for IIS?

Correct answer: Anonymous authentication

Explanation:

• Anonymous authentication is enabled by default in IIS and allows users to access content without providing credentials.

• By default, anonymous requests are processed using the built-in IUSR account or the application pool identity depending on IIS version and configuration.

• Other authentication modes such as Windows Authentication and Basic Authentication are disabled by default.

• Security note: Basic Authentication sends credentials encoded in base64 (not encrypted). If you enable it, always use HTTPS. Use Windows Authentication for integrated domain scenarios where NTLM/Kerberos is required.

How to change authentication in IIS:

1. Open IIS Manager and select the site or application.

2. Double-click Authentication in the Features View.

3. Enable or disable the desired authentication methods (for example, enable Windows Authentication to require domain credentials).