Port security is the best solution to prevent unauthorized devices, like a visitor's laptop, from connecting to the company's network. Port security can limit the number of devices that can connect to a network switch port and block unauthorized MAC addresses, effectively stopping unauthorized access attempts.
Web application firewall (WAF) protects against web-based attacks, not unauthorized network access.
Transport Layer Security (TLS) ensures encrypted communication but does not manage physical network access.
Virtual Private Network (VPN) secures remote connections but does not control access through physical network ports.