[pptp-server] Win 2K/XP - mppe-40 works, mppe-128 doesn't

[Josh Howlett]

> DON'T use both 40 & 128 bits! It causes weird behaviour.

If I don't specify mppe-40 the connection negotiates 128-bit MPPE, but
fails in the manner described below.

> More info would be nifty:
> OS, versions of pptpd, ppp, kernel, Patches applied, etc.
> Dump of both /etc/pptpd.conf and /etc/ppp/options(.pptp[d])

I have tried various kernels: 2.4.10, 2.4.16 and 2.4.18; patched with
linux-2.4.4-openssl-0.9.6a-mppe.patch.gz and
linux-2.4.16-openssl-0.9.6b-mppe.patch.gz.

I'm using ppp-2.4.1 patched with ppp-2.4.1-openssl-0.9.6-mppe-patch.gz.

options:

name server
auth
+chapms-v2
mppe-128
mppe-40
mppe-stateless
deflate 0
ms-dns ****
lcp-echo-failure 3
lcp-echo-interval 30

many thanks, josh.

> On Thu, 2002-06-13 at 15:14, Josh Howlett wrote:
> > Hi all,
> >
> > My problem is that under Windows 2K or XP, MPPE @ 128 bits does not
> > work correctly.  The link goes "up" but the encryption appears to fail
> > in some way.  I get the following in my logs:
> >
> > pppd[5312]: Unsupported protocol 0x3a20 received
> > pppd[5312]: Unsupported protocol 0x8719 received
> > pppd[5312]: Unsupported protocol 0x3dc received
> >
> > etc.
> >
> > If I *don't* specify "Require data encryption (disconnect if none)" in
> > the connection properties, then the link is negotiated at 40 bits
> > MPPE and works fine.
> >
> > It works fine under Windows 98.
> >
> > Any ideas?
> >
> > TIA, josh.
> >
> > ------------------------------------------------------------
> > Josh Howlett, Networking & Digital Communications,
> > Information Systems & Computing, University of Bristol, U.K.
> > 'phone: 0117 928 7850 email: josh.howlett at bris.ac.uk
> > ------------------------------------------------------------
> >
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> Richard de Vroede
> (r.devroede at linvision.com)
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>

------------------------------------------------------------
Josh Howlett, Networking & Digital Communications,
Information Systems & Computing, University of Bristol, U.K.
'phone: 0117 928 7850 email: josh.howlett at bris.ac.uk
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