Which VPN technology operates at the IP layer to secure traffic over untrusted networks?

Which VPN technology operates at the IP layer to secure traffic over untrusted networks?

• A. PPTP VPN
• B. SSH VPN
• C. IPsec VPN
• D. SSL/TLS VPN

Answer: (C)

The security of IP packets themselves across untrusted networks is what IPsec provides. It sits between the IP and transport layers, protecting each IP packet as it travels, using mechanisms like AH for integrity/authentication and ESP for confidentiality. This lets entire IP traffic between hosts or networks be secured, whether you’re connecting remote users or linking sites, by creating secure tunnels (tunnel mode) or securing just the payload (transport mode). Other options operate at higher levels or focus on specific application traffic. PPTP relies on PPP over GRE and isn’t an IP-layer solution for all IP traffic. SSH VPN tunnels traffic through an SSH connection, often at the application or session level. SSL/TLS VPNs secure traffic using SSL/TLS and typically protect application data over TCP rather than all IP packets across the network. For securing traffic at the IP layer across untrusted networks, IPsec is the appropriate choice.

The security of IP packets themselves across untrusted networks is what IPsec provides. It sits between the IP and transport layers, protecting each IP packet as it travels, using mechanisms like AH for integrity/authentication and ESP for confidentiality. This lets entire IP traffic between hosts or networks be secured, whether you’re connecting remote users or linking sites, by creating secure tunnels (tunnel mode) or securing just the payload (transport mode).

Other options operate at higher levels or focus on specific application traffic. PPTP relies on PPP over GRE and isn’t an IP-layer solution for all IP traffic. SSH VPN tunnels traffic through an SSH connection, often at the application or session level. SSL/TLS VPNs secure traffic using SSL/TLS and typically protect application data over TCP rather than all IP packets across the network. For securing traffic at the IP layer across untrusted networks, IPsec is the appropriate choice.