How do I enable routing to eth0 without having the ability to communicate amongst pptp clients? I know ip_forward = 1 makes routing of pptp clients possible, but i dont want communication under pptp clients.

1 Answer 1


You need to block traffic between users by packet filter.

  • You have any suggestion on how to achieve this using for iptables for example? My clients are connection using ppp0,ppp1,pppX and outgoing interface is eth0
    – ferdyh
    May 19, 2011 at 16:48
  • It would be more simple of your assign IPs to clients from dedicated subnet, so all you need is one rule per interface to deny traffic on given interface (pppX) to given subnet
    – AlexD
    May 19, 2011 at 17:02
  • all pppX devices get an ip and the eth0 is on a wan ip. I also cant seem to get internet traffic over my pptp tunnel. ip_forward is on...
    – ferdyh
    May 19, 2011 at 17:05
  • Seem to have fixed that now using iptables -t nat -A POSTROUTING -s -o eth0 -j MASQUERADE; Now only thing remaining is to block traffic between clients...
    – ferdyh
    May 19, 2011 at 17:10
  • All you need is something like iptables -A INPUT -i ppp0 -d -j REJECT somewhere in /etc/ppp/ip-up.d/
    – AlexD
    May 19, 2011 at 17:23

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.