A company is required to set up a secure connection between their headquarters and a remote office. The solution must work directly with the Internet Protocol to secure all traffic, support traversal through network address translators, and provide a mechanism for encryption and secure key management. What would be the most suitable protocol to employ for this scenario?
Point-to-Point Tunneling Protocol (PPTP)
Layer Two Tunneling Protocol (L2TP)
Internet Protocol Security (IPSec)
Secure Sockets Layer/Transport Layer Security (SSL/TLS)