- Virtual Private Networks for Network Layer Security

The IP network security issues that may be encountered range from soup to nuts, and include such things as eavesdropping, modification of packets in transit, spoofing, i.e., forged source IP addresses, and both man-in-the-middle and denial of service attacks. With all of this to contend with, there is clearly a need for secure IP layer solutions. However, there are additional needs for other layers, and they can be provided by virtual private networks using, e.g., Secure Socket Layer/Transport Layer Security (SSL/TLS) on the transport layer for web security, and on the application layer Secure/Multipurpose Internet Mail Extensions (S/MIME) can be used for email and Secure Shell (SSH) for a remote login shell. IPsec provides open standards for secure communications over the IP layer, and protects every protocol running on top of IPv4 and IPv6.