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 From:  Manuel Kasper <mk at neon1 dot net>
 To:  Hilton at QuarkAV dot com
 Cc:  m0n0wall at lists dot m0n0 dot ch
 Subject:  Re: [m0n0wall] XP PPTP Issue
 Date:  Sun, 22 Feb 2004 21:46:44 +0100
Hilton Travis wrote:

> Archie Cobbs on the MPD mailing list knows nothing of this XP PPTP issue
> - what is it exactly.  He says that "I don't know what the "XP PPTP
> issue" is, but there is an issue that could be related that relates to a

Well, enough people have reported problems with XP, PPTP and MPD at 
<http://sourceforge.net/mailarchive/forum.php?forum_id=32902>.

> certain ACK timeout in PPTP. This was changed from 10 to 1 second in
> FBSD 4.9, which should help in certain cases of high packet loss."

Not quite true. According to 
<http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/netgraph/ng_pptpgre.c>, 
it has been changed in FreeBSD 5.2 and 4-STABLE, but not 4.9. m0n0wall 
has had the patch (PPTP_MAX_TIMEOUT from 10 -> 1 second) since pb21. It 
seems to make things better, but does not completely resolve the issue 
(as one would expect, given that only a timeout value was changed).

> Is that the issue to which you are referring?  If not, please elaborate
> so we can see if this issue can also be solved.

It's been a while since I last tried it, but the symptoms were high 
packet loss (> 50%) and relatively high error counts reported in the 
Windows PPTP VPN connection status window. I used to think that the 
problem only occurred with Windows XP because at that time I only had 
problems with XP machines (BTW, even on completely standard FreeBSD 
systems with MPD, not just m0n0wall) while 2000 machines worked fine, 
but that may not necessarily be true. I switched to poptop in that 
application and it worked fine, but I really don't want to do this with 
m0n0wall because poptop is about 8 times slower since it uses userland 
PPP (and this can be really important on net45xxs, for example).

That said, personally I don't really care about it anymore since now 
that mobile user IPsec works, I don't use PPTP anymore. But there may be 
other m0n0wall users who are experiencing the same problem - step 
forward, please! :)

- Manuel