[arch-general] Forward all PPTP VPN packets to another proxy?

[Hexchain Tong]

On Sat, Mar 23, 2013 at 2:39 PM, Bill Sun <cap.sensitive at gmail.com> wrote:
>
> I'm thinking about running a http server that handles all the
> authentication for Server 2 (such as dante?), then forward all packets
> to that server (running in Server 1). But I don't know how to write
> corresponding iptables rules. So how to write such rules?

You need to setup another proxy on Server 1. Take squid for example,
in squid.conf, set upstream server using cache_peer and authentication
parameters (please refer to squid manual because I don't know how to
do it :-P ), and set a port that handles intercepted traffic (or it
won't work!):

http_port <local_squid_port> intercept

and insert the following iptables rule:

iptables -t nat -A PREROUTING -s <ip_addr_for_pptp> -p tcp --dport 80
-j REDIRECT --to-port <local_squid_port>