ccna book 200-125

ccna book 200-125.Using the IPSec protocol, secure site-to-site VPNs can be implemented between a central site and a remote site. o IPSec can also be used for remote access tunnels used by remote office access. The Cisco VPN Client is a way to establish IPSec remote access VPNs. In addition to IPSec, the Secure SocketsLayer (SSL) protocol can also be used to establish remote access VPN connections.8-1 VPNs8.1.1 VPN Overview8.1.1.1 VPN OverviewSolutions such as various encryption methods and PKI enable enterprises to securely extend their networks to the Internet ± o One way for enterprises to accomplish this extension is through a VirtualPrivate Network (VPN).A VPN is a private network created over a public network (usually the Internet) through tunneling technology. Instead of using a dedicated physical connection, a VPN uses a virtual connection to route an organization over the Internet to a remote site. The first generation of VPNs were strictly IP tunnels and did not include authentication or data encryption. For example, Generic Routing Encapsulation (GRE) is a tunneling protocol developed by Cisco that encapsulates multiple network layer protocol packet types into an IP tunnel. This creates a virtual point-to-point link through the IP interconnect network to a remote Cisco router. Other examples of VPNs that do not automatically include security measures are FrameRelay.ATMPVC and Multiprotocol Label Switching220 Chapter 8 Implementing Virtual Private NetworksLabelSwitching, MPLS) networks. A VPN is virtual because although it transmits messages within a private network, the messages are actually transmitted over the public network. VPNs are private because when traffic is transmitted over a public network, it is encrypted to protect the confidentiality of the data. A VPN is a communication environment with strictly controlled access, allowing only peer-to-peer connections that occur within a defined stakeholder. Confidentiality is achieved by encrypting the traffic within the VPN. Today, a secure implementation of VPN with encryption is often equated with the concept of a virtual private network. VPNs offer many advantages.Cost savings - VPNs enable organizations to connect remote offices and remote users to the main corporate site using cost-effective third-party Internet transport. VPNs do not require expensive WAN leased lines and modems. In addition, with the advent of cost-effective high-bandwidth technologies such as DSL, organizations can increase the bandwidth of remote connections while reducing connection costs with VPNs.Security - VPNs provide the highest level of security by using advanced encryption and authentication protocols to protect data from unauthorized access.