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Re: [LUG] pppd follow up question

 

On 08/04/14 16:53, Anthony Williams wrote:
> On 08/04/14 15:57, bad apple wrote:
>> On 08/04/14 15:08, Anthony Williams wrote:
>> Hi Anthony, did you fix your pppd-to-pppd issue from a while back?
> 
> I did, thanks.
> 
>> Just curious as to any solution you finally implemented, as that's the
>> sort of tricky thing I like to bookmark for future reference in case I
>> run into it myself again. 
> 
> In the end, I found from the client that there was a spare IP address on
> the subnet I could use, and everything was then fairly simple. I used a
> basic linux install with the same IP address on the intermediary end for
> each connection:
> 
> Server
> a.b.c.d
> ...ppp...
> a.b.c.x
> intermediary
> a.b.c.x
> ...ppp...
> a.b.c.e
> dial-in client
> 
> With a simple bit of iptables forwarding everything then just worked:
> 
> Dial-in client dials intermediary and is given a.b.c.e as IP address and
> a.b.c.x as gateway.
> 
> Dial-in client tries to connect to a.b.c.d.
> 
> a.b.c.x is the gateway, so it is sent via the intermediary system, which
> forwards everything to the remote server, and sends replies back through
> the intermediary.
> 
> Remote server and dial-in client unaware that there is the intermediary
> present, except the gateway address is a.b.c.x instead of a.b.c.d but
> this doesn't affect anything.
> 
> The intermediary itself now can't ping anything since it has two
> adapters with the same IP address, but it doesn't need to: it's just a
> router.
> 
> Anthony


Neat, and no mucking around with GRE tunnels and the like.

You would have been in for a much bigger headache without that spare
client IP address though!

Thanks for the info.

Regards


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