Site-to-site VPN and Remote access VPN
A Site-to-site VPN connect entire networks to each other. In a site-to-site VPN, hosts do not have VPN client software; they send and receive normal TCP/IP traffic through a VPN gateway and VPN gateway is responsible for encapsulating and encrypting outbound traffic, sending it through a VPN tunnel over the Internet.
The most common secure tunneling protocol used in site-to-site VPNs is the IPsec Encapsulating Security Payload (ESP).
Remote access VPNs connect individual hosts to private networks.In a remote access VPN, every host must have VPN client software .Here host tries to send any traffic, the VPN client software encapsulates and encrypts that traffic before sending it over the Internet to the VPN gateway at the edge of the target network.
Remote access VPN protocols are Point to Point Tunneling Protocol (PPTP) and Layer 2 Tunneling Protocol (L2TP)
Software based and Hardware based
Astaro Security Gateway
Secure Computing firewall/VPN family
Smoothwall Corporate Server
Mac OS X based:
Apple Mac OS X Server. Version 10.4 and higher supports authentication through certificates, Kerberos and group secrets.
Microsoft Windows 2000, Windows Server 2003 and Windows Server 2008. Windows 2000 does not support NAT-T when used as a server.
Microsoft Windows XP Professional and Windows 2000 Professional(small-scale VPN server but not included with XP Home)
Microsoft Windows Vista.
Microsoft ISA Server.
ISA Server based appliances.
Cisco PIX firewalls
Enterasys routers with VPN capabilities
IBM/ISS Proventia UTM
Juniper E-series and Netscreen series
Nortel VPN Routers
SonicWALL Firewall/VPN Appliances