[pptp-server] Re: Previous GRE: discarding out of order packet problem

[Eric H]

(please note the reply-to:eharashe at mediaone.net)
I seem to have the same problem. I'm connecting a Win98 computer over a
cable modem network to v1.1.1 pptpd. It works great for short packet
operations (ping, telnet). But if I try sending a file through ftp or
samba, it hangs after a variable amount of time. (Always within the
first 1-2MB) Almost each time (I'm not 100% certain it's each time), I get
a message such as:
May 14 17:06:05 Obsidian pptpd[22398]: Unexpected sequence number; got 265 after 263
May 14 17:11:43 Obsidian pptpd[22412]: Unexpected sequence number; got 5769 after 5767
May 14 17:28:01 Obsidian pptpd[22448]: Unexpected sequence number; got 95 after 93
May 14 17:28:01 Obsidian pptpd[22448]: Unexpected sequence number; got 98 after 96
May 14 17:31:06 Obsidian pptpd[22454]: Unexpected sequence number; got 804 after 802
May 14 17:35:32 Obsidian pptpd[22464]: Unexpected sequence number; got 70 after 67
May 14 17:42:30 Obsidian pptpd[22486]: Unexpected sequence number; got 802 after 796
May 14 17:42:32 Obsidian pptpd[22486]: Unexpected sequence number; got 822 after 820
May 14 17:43:05 Obsidian pptpd[22486]: Unexpected sequence number; got 2253 after 2240
May 14 17:43:32 Obsidian pptpd[22486]: Unexpected sequence number; got 3527 after 3525
May 14 17:43:43 Obsidian pptpd[22486]: Unexpected sequence number; got 3969 after 3967
May 14 17:43:52 Obsidian pptpd[22486]: Unexpected sequence number; got 4337 after 4335
May 14 17:44:27 Obsidian pptpd[22486]: Unexpected sequence number; got 5763 after 5761
... many more follow
I'm guessing it's some kind of packet re-ordering problem. I read some
of the code in pptpgre.c and pptpctrl.c and it seems that out of order
packets are dropped... It seems to be causing everything after that to not
work. After this happens, the link dies. That is, I can't connect through
the vpn connection to anything. On the server, I still see occasional
pppd: recvd [Compressed data] etc.


Eric Harashevsky (eharashe at mediaone.net)
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