[pptp-server] pptp, gre, adsl firewllas and nat

[John Leach]

On 23 May 2001 09:37:13 +1000, George Vieira wrote:

> Don't you need a kernel patch for NATed machines? forgot the name..   

Really?  I didn't know about this... have you any more information?  

I'll check the website again myself, thanks

> 
> 
> thanks,
> George Vieira
> 
> 
> -----Original Message-----
> From: John Leach [mailto:john at ecsc.co.uk]
> Sent: Tuesday, May 22, 2001 9:37 AM
> To: pptp-server mailing list
> Subject: [pptp-server] pptp, gre, adsl firewllas and nat
> 
> 
> Hello, I've been playing with pptpd with much success, but am having
> troubles getting it to work in one particular scenario.
> 
> I have 2 linux boxes, connect over the internet via a bridged cable
> internet connection on one end, and a natted adsl connection complements
> of the friendly British Telecom.
> 
> I'm using the linux client, and can connect to both boxes via their
> local LANs fine, all works great.
> 
> When I try to connect over the internet things go terribly wrong.  The
> port connects and the gre gets set up, ppp starts and seems to get
> going, but then I get LCP: ConfigRequest timeout errors (in my syslog).
> 
> I've found a bit of info on this message re: generic ppp problems. and
> have tried a few suggested solutions, for example playing with my mru
> and mtu settings, but to no avail.
> 
> I'm worried this is caused by the NATing of the adsl router.  I've
> tcpdumped traffic at both ends and observed seemingly normal gre and tcp
> traffic, so I'm pretty sure the router understands gre.  Could gre be
> being affected by the natting, like ipsec does?  (even tho ipsec is only
> affected because the changes in the packets by the NAT breaks the
> security measures, and gre has no such security measure I know of).
> 
> Has anyone else had similar problems?  I'm going to try this connection
> to a 3rd box on a real leased line, using the current boxes as a client
> one at a time to see if I can rule either of them out.
> 
> I'll submit more details when I get them.
> 
> John Leach.
> 
> _______________________________________________
> pptp-server maillist  -  pptp-server at lists.schulte.org
> http://lists.schulte.org/mailman/listinfo/pptp-server
> List services provided by www.schulteconsulting.com!
>