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

Thu Apr 29 01:08:23 UTC 2010
Les Mikesell <lesmikesell at gmail.com>

Dan Irwin wrote:
>> -----Original Message-----
>> From: centos-bounces at centos.org 
>> [mailto:centos-bounces at centos.org] On Behalf Of Rudi Ahlers
>> Sent: Wednesday, 28 April 2010 11:11 PM
>> To: CentOS mailing list
>> Subject: [CentOS] how to reroute all ADSL traffic via another 
>> server on theinternet?
>> Hi all,
>> Does anyone know, if it's possible to reroute all (i.e. HTTP / FTP /
>> DNS / SMTP / POP3 / IMAP / etc) from an ADSL connected machine via
>> another server, which is currently hosted with IS and has full
>> internet access?
>> i.e. Can I setup another machine, on a different public IP than the
>> dynamic ADSL IP as default gw? OR do I need todo something on that
>> machine to work as a router for such a setup?
>> Both servers in this case is CentOS linux, but I'm sure that won't
>> make a big difference?
> You could use GRE tunnelling, which is supported by Linux and Cisco
> among others.
> You could set up a GRE tunnel between your two sites, assign a /30 for
> the link, and route most traffic over the GRE interface (Minus the IP
> Address of your remote site - it must be routed via your internet
> connection).
> This will behave as a point-to-point link between your sites.
> Check out the ip(8) command, in particular the ip tunnel commands.
> But, something like this should be a nice start:
>  ip tunnel add Tunnel0 mode GRE remote
>  ifconfig Tunnel0 netmask
>  ip route add via

That could work approximately the same as a VPN - but you'll probably also have 
to source-NAT as you route on to internet destinations so the return packets 
will follow the same path back.

   Les Mikesell
    lesmikesell at gmail.com