http://cortex-m.com/counting-event/loader/prettify.css Being a specially programmed router, firewall usually gets connected with two or more physical network. The packets get filtered through the firewall while being transmitted from one network to another. Being present in between the site and the network connection, the firewall provides the opportunity to set up a centralized security policy. Being the simplest, the filter based firewalls are widely used in different sector. These firewalls can easily be configured with a table of addresses which are mainly responsible for the characterisation of the packets.
The term VPN stands for Virtual private Network. The VPN mainly provides well controlled connectivity while using a public network which can be the Internet. The IP tunnel is the main concept on which the VPN is based. This actually facilitates virtual point to point link between different arbitrary of a specified network. Though the IP address is usually provided at the end of the router, the virtual link is usually created at the entrance of the specific tunnel. Packets usually get encapsulated with the IP datagram while being sent from the router. Though the source address lies on the encapsulated router, the destination address is present in the IP header.
Many VPN users use different types of hardware firewalls to enrich their online privacy as well as security too. The VPN and the Firewalls can be combined in some ways i.e. i) Individual Computer to Remote Network via VPN through Firewall to Internet ii) Individual Computer to Remote Network via Firewall to VPN to Internet iii) Individual Computer to Remote Network via Firewall and VPN Combination in One Device to Internet. The user actually determines the arrangement according to his/her convenience but the 1st as well as the 3rd arrangement are mostly used as they are very much easy to configure.