Question

Difficulty: MediumVirtual Private Networks and Remote Access Security

Match each secure remote access protocol or tunneling technology on the left to its corresponding architectural characteristic and operational port specification on the right.

  • OpenVPNUses custom SSL/TLS protocols for key exchange and operates by default over UDP port 1194.
  • IPsec (IP Security)Operates at the Network Layer (Layer 3) utilizing IKEv2 over UDP port 500/4500 and ESP (IP Protocol 50) for encrypted payloads.
  • GRE (Generic Routing Encapsulation)Encapsulates Layer 3 multiprotocol packet types but lacks native encryption, requiring pairing with ESP for confidentiality.
  • SSTP (Secure Socket Tunneling Protocol)Establishes an SSL/TLS tunnel over TCP port 443, making it effective at traversing strict firewalls and NAT devices.

Answer

OpenVPN matches with UDP port 1194 SSL/TLS operation; IPsec matches with Layer 3 IKEv2/ESP functionality; GRE matches with unencrypted multiprotocol tunneling; SSTP matches with TCP port 443 SSL/TLS firewall traversal.
OpenVPN defaults to UDP port 1194 and uses SSL/TLS. IPsec functions at Layer 3 using IKEv2 (UDP 500/4500) and ESP (IP Protocol 50). GRE provides tunneling for multicast/multiprotocol traffic without native encryption. SSTP wraps PPP traffic inside SSL/TLS over TCP port 443 to pass through strict firewalls.

Step-by-Step Solution

1
Analyze OpenVPN operational traits
Identify that OpenVPN leverages custom SSL/TLS mechanisms and defaults to UDP port 1194.
Matching protocol transport ports ensures correct firewall rule configuration.
2
Identify IPsec protocol behavior
Recognize that IPsec operates at Layer 3, utilizing IKEv2 (UDP 500/4500) and ESP for packet encryption.
IPsec provides native suite-level security across network boundaries.
3
Evaluate GRE capabilities
Confirm GRE supports routing protocols and multicast but lacks native encryption capabilities.
Distinguishing encapsulation protocols from cryptographic protocols prevents security misconfigurations.
4
Examine SSTP transport mechanism
Associate SSTP with TCP port 443 HTTPS traffic for seamless firewall and proxy traversal.
SSTP encapsulates PPP inside SSL/TLS over standard web traffic ports.

Key Concept

Virtual Private Network Protocols and Encapsulation Characteristics
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