[pptp-server] Win98 & encryption -- Unsupported protocol error

[Matthias Suencksen]

> Matthias,
>
> I think this has the same cause as the compressed data error.  The problem
> is that if a packet gets dropped or comes in out-of-order (which causes it
> to be dropped in pptpd 1.0.1) the ppp_mppe module loses sync and never
> recovers.  The patch described below should fix that problem.  If the
> problem is with out-of-order packets, then using pptpd-1.1.2 will also help.

I forgot to mention that patch is already applied - if I remove the patch I get the
messages you quoted from the FAQ. I also use pptpd-1.1.2 and the strip-domain
and require-mpppe patches.

The log records some packet-reordering messages and after some time
lots of the following:

Oct 29 20:28:44 x pppd[11170]: sent [LCP ProtRej id=0xb 51 19 eb 51 37 79 aa 67 fd 5d 78 67 9f 80 2b dd e0 e0 25 e5 bb 3c 46 b9 20 bc 5d a0 bf 4e 99 b9 4b 0e 12
 54 ef 07 b5 c5 df 85 7f b6 c6 4c bc 40 c6 73 ed 40 02 ea 25 dc 61 fa 77 2a b0 59 c4 5f fc ae 9e d8 9e a6 60 5b d4 87 27 cd c4
Oct 29 20:28:45 x pppd[11170]: rcvd [proto=0xbe1b] df 60 4e 4e 84 f1 89 a7 ef 18 38 6d 32 7d c1 f6 85 f8 d7 6a 37 9e e0 28 9c b3 0c b9 a3 81 8e 68 ...
Oct 29 20:28:45 x pppd[11170]: Unsupported protocol 0xbe1b received
Oct 29 20:28:45 x pppd[11170]: sent [LCP ProtRej id=0xc be 1b df 60 4e 4e 84 f1 89 a7 ef 18 38 6d 32 7d c1 f6 85 f8 d7 6a 37 9e e0 28 9c b3 0c b9 a3 81 8e 68 bd
 dc e7 b1 2a 29 bf 3e 14 2a 3d 6d bf e8 ca c3 68 0d 3a 45 d4 b8 30 2c e1 a7 96 55 77 46 0d 42 3e ec fd 17 72 76 07 b2 29 0f 18
Oct 29 20:28:45 x pppd[11170]: rcvd [proto=0xf407] d5 4b 12 e9 75 ae 4a 4c fc f0 ba c8 e4 75 65 d3 22 67 37 f9 ab fa ca f0 ff d7 47 64 dd 4b 9f 63 ...
Oct 29 20:28:45 x pppd[11170]: Unsupported protocol 0xf407 received
Oct 29 20:28:45 x pppd[11170]: sent [LCP ProtRej id=0xd f4 07 d5 4b 12 e9 75 ae 4a 4c fc f0 ba c8 e4 75 65 d3 22 67 37 f9 ab fa ca f0 ff d7 47 64 dd 4b 9f 63 88
 89 f6 fc cd 8f 3c 1d 02 a0 22 f9 fb 53 91 14 bc c4 46 ea e6 e6 95 6e f2 9f 5f 83 0d 62 bd 00 a7 4c b0 fe ef b3 29 08 7c b6 bf
Oct 29 20:28:45 x pppd[11170]: rcvd [proto=0xdd29] 30 f2 bb 78 24 a9 09 95 12 42 6f 3d 30 9b 49 a0 1a 3b f2 b3 d0 99 81 45 45 f1 31 c2 45 b3 c3 9f ...
Oct 29 20:28:45 x pppd[11170]: Unsupported protocol 0xdd29 received

.. looked already at the source code but it's difficult to know 
where to start debugging ..

Matthias