I just set up a PPTP VPN server on the vps. Now I can connect my VPN server with windows 7 and I can ping/traceroute any websites successfully after VPN connection, but I'm unable to browse internet via VPN connection. It seems DNS works fine but data transfer or something on routing failed.

BTW: /var/log/messages says:

pppd 2.4.4 started by root, uid 0
Using interface ppp0
Connect: ppp0 <--> /dev/pts/0
CTRL: Ignored a SET LINK INFO packet with real ACCMs!
MPPE 128-bit stateless compression enabled
Cannot determine ethernet address for proxy ARP
local  IP address 192.168.25.1
remote IP address 192.168.25.31

I'm confused by the message "Cannot determine ethernet address for proxy ARP". I'm a newbie and I have no idea what's wrong with it.

If you have any solutions to this issue I will be much appreciated.

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CentOS 5.6 Profile (Latest 3.0 (3.0.4-linode38))
Installed applications: Kloxo, webmin

below is my config for pptp vpn server:

yum install -y ppp iptables
mkdir pptpd-install
cd pptpd-install
wget  http://poptop.sourceforge.net/yum/stable/packages/pptpd-1.3.4-2.rhel5.i386.rpm
rpm -ivh pptpd-1.3.4-2.rhel5.i386.rpm


--------  conf begin ---------------

/etc/pptpd.conf
localip 192.168.25.1
remoteip 192.168.25.31-35


/etc/ppp/options.pptpd
ms-dns 8.8.8.8
ms-dns 8.8.4.4

/etc/ppp/chap-secrets
vpn_id pptpd vpn_pwd *

/etc/sysctl.conf
net.ipv4.ip_forward = 1
# net.ipv4.tcp_syncookies = 1

/etc/sysconfig/iptables-config
# IPTABLES_MODULES="ip_conntrack_netbios_ns"

--------  conf end ---------------

sysctl -p 

cd /etc/init.d
mv iptables ~/iptables.bak
wget http://epoxie.net/12023.txt && cat 12023.txt | tr -d ‘\r’ > iptables
chmod +x iptables
rm -rf 12023.txt

mknod /dev/ppp c 108 0

iptables -t nat -A POSTROUTING -s 192.168.25.0/24 -o eth0 -j MASQUERADE

/etc/init.d/iptables save
/etc/init.d/iptables restart
/etc/init.d/pptpd restart
chkconfig pptpd on
chkconfig iptables on

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Why bother? PPTP has been cracked for well over a decade, it's the screendoor of VPN protocols. Waaaaaay better to use OpenVPN which is actually secure.