From the Nmap results:

Service Analysis:

SSH (22): Secure Shell is a remote access protocol that is typically well-secured with encryption and authentication mechanisms. It’s not the easiest to exploit without valid credentials or known vulnerabilities.

SMTP (25): The port is filtered, which indicates that it might be blocked by a firewall, making it less accessible as an attack vector.

RPCBind (111): RPC services can sometimes expose vulnerabilities, but they are less common in modern systems.

NFS (2049): Network File System is a file-sharing service. Misconfigured NFS servers often expose sensitive files or directories that can be accessed without proper authentication.

Best Target:NFS (port 2049) is the most attractive target. Attackers can exploit insecure exports, gain unauthorized access to shared directories, or elevate privileges if the server allows root access over NFS.

CompTIA Pentest+ References:

Domain 2.0 (Information Gathering and Vulnerability Identification)

Domain 3.0 (Attacks and Exploits)