vpnc
Cisco-compatible VPN client
vpnc is a VPN client compatible with cisco3000 VPN Concentrator (also
known as Cisco's EasyVPN equipment). vpnc runs entirely in userspace
and does not require kernel modules except of the tun driver to
communicate with the network layer.
It supports most of the features needed to establish connection to the
VPN concentrator: MD5 and SHA1 hashes, 3DES and AES ciphers, PFS and
various IKE DH group settings.