Event Code 4625 in Windows logs indicates a failed logon attempt. This could be a sign of someone trying to guess the credentials of a valid user account by repeatedly trying different passwords or usernames. This is known as a brute force attack and can be used to gain unauthorized access to a system or network. References:
https://www.cisco.com/c/en/us/td/docs/security/ise/2-4/admin_guide/b_ise_admin_guide_24
/b_ise_admin_guide_24_new_chapter_01110.html

What Are Ports 139 And 445? SMB has always been a network file sharing protocol. As such, SMB requires network ports on a computer or server to enable communication to other systems. SMB uses either IP port
139 or 445. Port 139 - SMB originally ran on top of NetBIOS using port 139. NetBIOS is an older transport layer that allows Windows computers to talk to each other on the same network. Port 445 - Later versions of SMB (after Windows 2000) began to use port 445 on top of a TCP stack. Using TCP allows SMB to work over the internet. https://www.varonis.com/blog/smb-port SMB Ports 139 and 445 are open Email Ports 25 and 110 are closed Therefore "D. Email Ports are closed on the Server."

A false positive in network security is when a benign action is incorrectly flagged as malicious, leading to legitimate traffic being blocked. This can disrupt normal network operations and access to services, as the security system mistakenly identifies normal behavior as a threat1.
References := The concept of false positives and their impact on network traffic is discussed in various cybersecurity resources, including Cisco's own training materials and discussions on network security best practices1.

Application whitelisting/blacklisting is a technology used to control which applications are allowed to execute on a company's corporate PCs. Whitelisting allows only approved applications to run, while blacklisting prevents specific applications from running. This approach is effective for managing application usage across an enterprise.