[CentOS] how to reroute all ADSL traffic via another server on the internet?

Wed Apr 28 14:57:25 UTC 2010
Simon Billis <simon at houxou.com>

Rudi Ahlers sent a missive on 2010-04-28:

> And I haven't been able to install openvpn on the ADSL hosted server
> either, so I want to try a gateway type setup

Having given this some thought I think that you would do better to provide
proxy services on a case by case basis.

Attempting to route traffic using a default gateway I don't think is going
to work... the "next hop" is not on a local subnet so I don’t think this is
going to work (I might be wrong about this).

You could have a vpn between the machines - the ADSL gateway machine have a
VPN to the IS machine and all traffic from and to the ADSL machine/NAT
network behind it is routed over the VPN. This does work and is fairly easy
to set-up if you have access to the ADSL machine.

If you can't set this up then I think that you should concentrate on
providing proxy services for essential services i.e. http, smtp, pop3, imap,
ftp (if needed). Squid will do some, you can then use a mail server of your
choice to provide smtp relay services, I think that there is a pop3/imap
proxy out there also (I've never used one though). For such services the
adsl gateway machine can then do DNAT on the outbound packet (using iptables
prerouting table) and then the proxied service will then do its thing

By far the best solution requiring little effort is a vpn (imho).