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Date:      Thu, 26 Jun 2003 20:24:39 -0500 (CDT)
From:      Archie Cobbs <archie@dellroad.org>
To:        Doug Lee <dgl@dlee.org>
Cc:        Kris Kennaway <kris@obsecurity.org>
Subject:   Re: mpd VPN won't work after upgrade from 4.6-STABLE to 4.8-STABLE
Message-ID:  <200306270124.h5R1Oeb2008887@arch20m.dellroad.org>
In-Reply-To: <20030625222534.GD478@kirk.dlee.org>

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Doug Lee wrote:
> > If you're getting protocol reject errors -- while trying to use
> > Microsoft MPPE encryption? Then probably one side is generating
> > the keys incorrectly. What is the other side? Also, let's see
> > the log trace.
> 
> Here is a trace consisting of link-up, responses to a set of five
> pings, and link-terminate, all from the originating side, which is the
> 
> ...
> 
> One specific question, other than "Why won't this work?" :-) :  What's
> this line doing in here at the end of the successful CHAP negotiation:
> 
> 17:35:00  MESG: S=181EBCAE417331F125BCDDB3991C14EF7B39750D 

This is Microsoft overloading the CHAP message string with
their reverse authentication hash. It's normal with MS-CHAP.

> The following mpd log entries were generated by a set of five pings
> I attempted to send up the link:
> 
> 17:35:15 [vpn] LCP: rec'd Protocol Reject #22 link 0 (Opened) 
> 17:35:15 [vpn] LCP: protocol 0x0023 was rejected 
> 17:35:16 [vpn] LCP: rec'd Protocol Reject #23 link 0 (Opened) 
> 17:35:16 [vpn] LCP: protocol 0x00e7 was rejected 
> 17:35:17 [vpn] LCP: rec'd Protocol Reject #24 link 0 (Opened) 
> 17:35:17 [vpn] LCP: protocol 0x0087 was rejected 
> 17:35:18 [vpn] LCP: rec'd Protocol Reject #25 link 0 (Opened) 
> 17:35:18 [vpn] LCP: protocol 0x006d was rejected 
> 17:35:19 [vpn] LCP: rec'd Protocol Reject #26 link 0 (Opened) 
> 17:35:19 [vpn] LCP: protocol 0x16a1 was rejected 

Again, what's on the other side of the link? Is it necessary
to enable MS-CHAP in both directions? The other side is screwing
up MPPE key generation. Note that with MS-CHAPv2, the server is
authenticated as well anyway, so you really only need to authenticate
in one direction.

-Archie

__________________________________________________________________________
Archie Cobbs     *    Halloo Communications    *     http://www.halloo.com



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