Which protocol is used to secure key exchanges during client-to-server VPN connections and is commonly used with IPsec?

Which protocol is used to secure key exchanges during client-to-server VPN connections and is commonly used with IPsec?

• A. TLS
• B. SSH
• C. ISAKMP
• D. LDAP

Answer: (C)

The key idea here is how an IPsec VPN securely negotiates and manages the cryptographic parameters before any protected traffic is sent. ISAKMP provides the framework for negotiating, establishing, and maintaining security associations and the cryptographic keys that IPsec uses. In practice, when a client connects, ISAKMP (often in conjunction with IKE) handles authenticating the endpoints and agreeing on the encryption algorithms, keys, and lifetimes that both sides will use. Once these SA parameters are established, IPsec can protect traffic with ESP or AH according to what was agreed. This is why this protocol fits the scenario of client-to-server VPNs and IPsec. Other options serve different purposes: TLS secures end-to-end sessions in SSL/TLS VPNs but isn’t the key-exchange protocol for IPsec; SSH is for secure remote administration; LDAP is for directory services.

The key idea here is how an IPsec VPN securely negotiates and manages the cryptographic parameters before any protected traffic is sent. ISAKMP provides the framework for negotiating, establishing, and maintaining security associations and the cryptographic keys that IPsec uses. In practice, when a client connects, ISAKMP (often in conjunction with IKE) handles authenticating the endpoints and agreeing on the encryption algorithms, keys, and lifetimes that both sides will use. Once these SA parameters are established, IPsec can protect traffic with ESP or AH according to what was agreed.

This is why this protocol fits the scenario of client-to-server VPNs and IPsec. Other options serve different purposes: TLS secures end-to-end sessions in SSL/TLS VPNs but isn’t the key-exchange protocol for IPsec; SSH is for secure remote administration; LDAP is for directory services.