Page 222 - DCAP311_DCAP607_WIRELESS_NETWORKS

Wireless Networks

Notes VPNs allow employees to securely access their company's intranet while traveling outside the
office. Similarly, VPNs securely and cost effectively connect geographically disparate offices of
an organization creating one cohesive virtual network. VPN technology is also used by ordinary
Internet to connect toproxy servers for the purpose of protecting one's identity.
!
Caution To prevent disclosure of private information, VPNs typically allow only
authenticated remote access and make use of encryption techniques.
VPNs provide security by the use of tunneling protocols and through security procedures such
as encryption. The VPN security model provides:
z z confidentiality such that even if the network traffic is sniffed at the packet level (see network
sniffer and Deep packet inspection), an attacker would only see encrypted data

z z sender authentication to prevent unauthorized users from accessing the VPN.
z z message integrity to detect any instances of tampering with transmitted messages
Secure VPN protocols include the following:
z z Internet Protocol Security (IPsec) as initially developed by the Internet Engineering Task
Force (IETF) for IPv6, which was required in all standards-compliant implementations
of IPv6 before RFC 6434 made it only a recommendation. This standards-based security
protocol is also widely used with IPv4 and the Layer 2 Tunneling Protocol. Its design meets
most security goals: authentication, integrity, and confidentiality. IPsec uses encryption,
encapsulating an IP packet inside an IPsec packet. De-encapsulation happens at the end
of the tunnel, where the original IP packet is decrypted and forwarded to its intended
destination.

z z Transport Layer Security (SSL/TLS) can tunnel an entire network's traffic (as it does in
the OpenVPN project) or secure an individual connection. A number of vendors provide
remote-access VPN capabilities through SSL. An SSL VPN can connect from locations
where IPsec runs into trouble with Network Address Translation and firewall rules.

z z Datagram Transport Layer Security (DTLS) - used in Cisco Any Connect VPN and
in OpenConnect VPN[9] to solve the issues SSL/TLS has with tunneling over UDP.
z z Microsoft Point-to-Point Encryption (MPPE) works with the Point-to-Point Tunneling
Protocol and in several compatible implementations on other platforms.

z z Microsoft Secure Socket Tunneling Protocol (SSTP) tunnels Point-to-Point Protocol
(PPP) or Layer 2 Tunneling Protocol traffic through an SSL 3.0 channel.
z z Multi Path Virtual Private Network (MPVPN). Ragula Systems Development Company
owns the registered trademark "MPVPN".
Secure Shell (SSH) VPN – Open SSH offers VPN tunneling (distinct from port forwarding) to
secure remote connections to a network or to inter-network links. Open SSH server provides
a limited number of concurrent tunnels. The VPN feature itself does not support personal
authentication.

Self-Assessment

Fill in the blanks:
7. A ................................... attacker entices computers to log into a computer which is set up as
a soft AP
8. ................................... poisoning is a type of attack where the Media Access Control (MAC)
address is changed by the attacker.

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