[pptp-server] a *bizarre* situation

[John Leach]

On 10 Jun 2001 21:08:23 +0100, John Leach wrote:

Ok, further information...
tested with win98 and the encrypted traffic works fine, so I'm assuming
it is the win2k settings until I've tested things further (maybe like
made sure win98 is using 128bit mppe rather than 40bit)

I have tested many different configuration combinations, including raw
copies of win2k examples from the pptp site and others but still to no
avail.  I have even tried a config from my rpm which I confirmed to work
a month ago or so, I'm still a bit lost about why its suddenly not
working, and why its not working in such a bizarre way, does anyone know
why this happens technically?

I'll get back more info as soon as I finish fiddling around with other
quite bizarre slightly unrelated problems... :)

John Leach.
 

> 
> Ok, now this has me doing some serious swede scratching....
> 
> This is over a local lan, with no firewalls or routers in between, just
> a switch.
> 
> I have a Win2k client (actually 2, one advanced server, another pro SP2)
> connecting to pptpd v1.1.2, pppd 2.4.0 (with the relevant patches to
> make mppe work), on Linux kernel 2.4.3 again with the relevant patches.
> 
> I connect un-encrypted, everything works fine, things work superbly in
> fact.
> 
> I connect using encryption, and everything *seems* to work fine.  auths,
> connects, sets up the tunnel...  but the win2k box doesn't seem to
> actually *see* the packets it receives.  But it definately does get
> them.
> 
> A simple ping test from the win2k box to the other end of the ppp
> connection results in an outgoing icmp request which the linux server
> receives ok, which then replies with an icmp reply, which arrives at the
> other end of the tunnel fine too, but the win2k box doesn't see it.
> 
> I know the packets are being received as I've used WinEthereal and have
> captured them.  I've tried this with TCP connections too, win2k just
> doesn't see the ack packets even tho they actually get received.
> 
> To be truthful I'm faffing around with an rpm I made last month of this
> lot, which I've tested before and has been confirmed to work, I *should*
> be recompiling from source manually and re-testing, but I'd really like
> to know what is going on.
> 
> There are *no* packet filters of any kind active on either win2k box or
> the linux box.  I wanted to test via the linux pptp client but I can't
> seem to make it use mppe, it always defaults to cleartext. 
> 
> This has me stumped.  I first thought data was being corrupted
> somewhere, but ethereal should pick up on that (I beleive it checks the
> crcs).  I can see the incoming gre packets, and the resulting
> un-encapsulated packets, but win2k never seems to actually use them.
> 
> ARGH!
> 
> John Leach. MCP, CCNA, BOFH, EGO.
> 
> 
> 
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