What is a VPN?
A Virtual Private Network is a type of a connection that connects remote user s to their central office using internet. An IPSEC VPN is virtual tunnel through your public ISP network. VPN are highly encrypted and secure connections.
how to setup a vpn on Cisco:
This article is about the VPN site to site CLI configuration on GNS3, It’s not so much the commands.
I shall divide these configurations into few parts to make it easy to understand i.e.
1. Define isakmp policy and transform set:
Isakam is the protocol that allow all of keys exchange to happen automatically no need to manually configure the VPN. In this step we shall define authentication type, encryption type, hash. Lifetime and define what session keys are used.
2. Create an ACl
Define interesting traffic using an access control list, this ACL is not for deny or permitting some IP addresses but it just says which addresses are encrypted
3. Set up cryto Map and assign this to interface:
In this step we shall tie up all piece so that we can apply to an interface