HashFunction :( (MD5,SHA-1is a formula used to convert a variable-length message into a single .string of digits of a fixed length
: VPN protocols L2TP (layer 2 tunneling protocol): is used to create a media-independent , multiprotocol virtual private dialup network (VPDN)…….but it does not provide encryption. GRE(Generic routing encapsulation ) : with GRE tunneling cisco router at each site encapsulates protocol specific packets in IP HEADER creating point to point link to cisco router at other of an Ip cloud ,where the IP header is stripped off . IPsec( IP security protocol ): is the choice for secure corporate VPNs .it can provide the security service using internet key exchange (IKE) to handle negotation of protocols and algortithms based on local polivy and to generate the encryption and authentication key to be used by IPSec.
Internet Key Exchange (IKE): used to esablish ashared security policy and authentication keys for services such as IPSec that require keys . one of its protocols is ISAKMPInternet Security Association and Key Management Protocol (ISAKMP): it is protocol used for implementing akey exchange and negotation of security association (SA)
Security association (SA): It is the security database that contains all the security policy that the VPN will based on. This security database contains that:1-authentication ,encryption algorithm.2-specification of network traffic.3-IPsec protocols .4-IPsec modes .
:IPsec protocols Encapsulating Security Payload (ESP): a security protocol that provide data encryption and production with optional authentication …it can completely encapsulates user data Authentication Header (AH): a security protocol that provide authentication .it can be used either by itself or with ESP
Tasks to Configure IPSec (site to(site Task 1 – Prepare for IKE and IPSEC Task 2 – Configure IKE Task 3 – Configure IPSec Task 4 – Test and Verify IPSEC
Step1- Determine IKE(IKE Phase 1( PolicyDetermine the following policy details: Key distribution method Authentication method IPSec peer IP addresses and hostnamesIKE phase 1 policies for all peers Encryption algorithm Hash algorithm IKE SA lifetimeGoal : setup a secure commuication channel for negotiation of IPSec SA in phase2
Step2-Determine IPSec (IKE Phase 2( PolicyDetermine the following policy details: IPSec algorithms and parameters for optimal security and performance IPSec peer details IP address and applications of hosts to be protected IKE-initiated SasGoal : these are security parameters used to protect data and messages exchanged between end points
Step 3—Create Crypto ACLs using ExtendedAccess Lists
Purpose of Crypto MapsCrypto maps pull together the various parts configured for IPSec, including The traffic to be protected by IPSec and a set of SAs The local address to be used for the IPSec traffic The destination location of IPSec-protected traffic The IPSec type to be applied to this traffic
Display your configured IKE policies .show crypto isakmp policy Display your configured transform sets. show crypto ipsec transform set Display security associations show crypto isakmp sa Display the current state of your IPSec SAs. show crypto ipsec sa Display your configured crypto maps. show crypto map Enable debug output for IPSec events. debug crypto ipsec Enable debug output for ISAKMP events. debug crypto isakmp
:VPN Remote access The requirements for VPN Servers include the need for Internet Security Association and Key Management Protocol (ISAKMP) policies using Diffie-Hellman. The VPN Remote feature does support transform sets providing Both encryption and authentication ; so it does not support Authentication Header (AH) authentication.
AAA (authentication, authorization and accounting) servers :are used for more secure access in a remote-access VPN environment.AAA then checks the following: Who you are (authentication) What you are allowed to do (authorization) What you actually do (accounting)The accounting information is especially useful for tracking client use for security auditing, billing or reporting purposes
: VPN Client The installation of the Cisco VPN Client is a very straightforward process. A number of tasks must be completed to establish connectivity to a VPN head-end. just start setup and the Welcome screen will be presented
The Connection Entries screen is capable of holding multiple entries should multiple access sites. Click the New button at the top of the screen to open the Create New VPN Connection Entry dialog box, shown in Figure
Authentication Tab Group Authentication—A username and password is necessary to complete the VPN profile.
Transport Tab The Transport tab allows the configuration of transparent tunneling as well as the choice of whether to use IPsec over UDP or TCP.
Backup Servers Tab: The VPN client contains a Backup Servers tab to configure a single connection with the capability to connect to multiple servers.
Finish the Connection Configuration From the main VPN Client window, you can establish a VPN connection by highlighting one of the profiles and clicking the Connect button at the top of the window. If the connection parameters were properly configured, the VPN connection is successful.
After a VPN connection is established, various statistics about the connection are available. From the Status pull-down menu, select Statistics. This launches the Statistics window.