[pptp-server] Packet ordering problem

[Michel Stempin]

Hi list,

I guess I am experiencing some packet reordering problems. Here is my
config:
	- linux 2.0.36
	- pppd 2.3.8 + mppe patch
	- pptpd 1.1.2

Everything is working fine, but the connection dies (esp. during long FTP
transfers ;-)) for what looks like a packet ordering problem. I formely used
pptpd 1.0.1 and switched to 1.1.2, for no better results.

You will find below what I get in the logs, but stated shortly, packet 833
is out of order. What surprises me, is that this packet is not waited for
long before giving up (see timestamp). Looking at the code, isn't it
supposed to be waiting for 2s?

pptpgre.h:35:#define PCKT_REORDER_WAIT_TIME 2

Trying to solve my problem, do you think that lowering the MTU value from
the default (Windows) 1500 would do anything good to me?

----------- log start
Jul  4 16:26:07 ns pppd[17225]: rcvd [CCP ResetReq id=0x13]
Jul  4 16:26:07 ns pppd[17225]: sent [CCP ResetAck id=0x13]
Jul  4 16:26:15 ns pptpd[17224]: Buffering out-of-order packet; got 834
after 832
Jul  4 16:26:15 ns pppd[14708]: rcvd [LCP EchoReq id=0x8e magic=0x0 04 05 06
07 08 09 0a 0b 0c 0d 0e 0f 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f
20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 00
00 00 00]
Jul  4 16:26:15 ns pppd[14708]: sent [LCP EchoRep id=0x8e magic=0xa37f 04 05
06 07 08 09 0a 0b 0c 0d 0e 0f 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e
1f 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37
00 00 00 00]
Jul  4 16:26:15 ns pptpd[17224]: Buffering out-of-order packet; got 835
after 832
Jul  4 16:26:15 ns pptpd[17224]: Buffering out-of-order packet; got 836
after 832
Jul  4 16:26:15 ns pptpd[17224]: Gave up waiting for 1 lost packets
beginning with 833
Jul  4 16:26:15 ns pppd[17225]: rcvd [Compressed data] 13 23 9e 1b 1d e9 37
33 ...
Jul  4 16:26:15 ns pppd[17225]: rcvd [proto=0x58d6] 0d 2d 48 3b e7 54 f6 3e
bb a6 94 10 70 dc 05 15 2b 7e 01 f6 ac 61 66 dc 95 61 d3 12 a0 68 db 2a ...
Jul  4 16:26:15 ns pppd[17225]: Unsupported protocol (0x58d6) received
Jul  4 16:26:15 ns pppd[17225]: sent [LCP ProtRej id=0x2 58 d6 0d 2d 48 3b
e7 54 f6 3e bb a6 94 10 70 dc 05 15 2b 7e 01 f6 ac 61 66 dc 95 61 d3 12 a0
68 db 2a 03 69 3d 2f 29 ec 78 56 6b 5b 6e 6c 20 28 38 93 78 df a0 e5 8f a0
79 17 c2 e4 79 2b 4c 9f c1 d7 42 01 de 2b 6d 10 80 9d 73 8e d5
----------- log end

--
Michel Stempin
MIS
COM One SA, 11 parc de Marticot, 33610 CESTAS, FRANCE
Tel: +33(0)5 57 97 72 72
Fax: +33(0)5 56 78 84 78
Email: mstempin at com1.fr