I have a CentOS server configured as a PPTP VPN Server. The client is a Windows 7 with "Use default gateway on remote network" in advanced TCP/IPv4 properties enable. He can connect to CentOS without any problem and can access to: The Box of his ISP (http://192.168.1.254/) The CentOS server The website which is hosted by the server (through http://) But he canNOT access any other web service (google.com or 74.125.230.224) I am a beginner with web servers so I do not know what can cause this problem. Note 0 : The Windows 7 user must be able to access the whole internet through the CentOS PPTP proxy. Note 1 : With "Use default gateway on remote network" in advanced TCP/IPv4 UNCHECKED it is the same problem Note 2 : With "Use default gateway on remote network" in advanced TCP/IPv4 UNCHECKED AND "disable class based route addition" CHECKED the Win 7 can access google but with the ISP IP (no use of the VPN...) See Screenshot Note 3 : I have made a echo 1 > /proc/sys/net/ipv4/ip_forward and a iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE