Please disregard the published answer to this question. This was not answer the interviewer looking for. The question is how do you use VPN to connect branch office to the other office. Not asking for explanation about VPN. Whoever who wrote the response has absolutely no knowledge about MAC address and IP address. He doesn't even know MAC addresses do not cross the segment and no knowledge about NAT (Network Address Translation) when he talks about IP addressconflicts. Best way to connect branch offices via VPN is to have VPN concentrator (Cisco, Nortel or a SOHO VPN enabled routers) installed and create LAN-to-LAN VPN tunnels between the offices. There are so many ways to accomplish this at varying costs.