In this lesson we’ll take a look how to configure remote access IPsec VPN using the Cisco VPN client. This allows remote users to connect to the ASA and access the remote network through an IPsec encrypted tunnel.
The remote user requires the Cisco VPN client software on his/her computer, once the connection is established the user will receive a private IP address from the ASA and has access to the network.
The Cisco VPN client is end-of-life and has been replaced by the Cisco Anyconnect Secure Mobility Client. It’s not supported any more but still widely in use nowadays.
This is the topology that we will use for this example:
Many companies have multiple remote offices which need secure network connectivity with the headquarters or between them. This can be achieved by using a site-to-site VPN setup which allows offices in multiple fixed locations to establish secure connections and share resources with each other over a public network such as the Internet. Cisco ASA supports the IPsec protocol for configuring an site-to-site VPN tunnel. IPsec works by authenticating and encrypting each IP packet of a communication session and uses the Internet Key Exchange (IKE) protocol to negotiate and establish a secure VPN tunnel. The original IKE version 1 is defined in RFC 2409 and the IKE version 2 (IKEv2) is defined in RFC 5996. Cisco introduced support for IKEv2 beginning with ASA version 8.4 but in this article we will focus only on the legacy IKEv1 implementation.