MPD Issues - Errors and Mysterious Packet Loss

[Dan Hardiker]

> [Dan Hardiker]
> I have since managed to find (on the source forge mpd mailing list not
> mentioned on the mpd homepages) someone else with an identical problem
(who
> was advised to install a TCP-MSS patch). It appears that the problem lies
> with XP connected to MPD using a VPN. Actually on reflection - it was you
> who suggested it!
>
> For reference:
>
http://sourceforge.net/mailarchive/forum.php?thread_id=3083368&forum_id=32902

The patch was faulty - a number of hunks failed (all down to incorrect line
numbers) ... and in any case, the patch doesnt appear to work. Same problem
exactly.

I did, however, run TCP dump and found that all pings I sent got a reply ...
but only 30% of them made it back to the client

[10:09:13][root at armadillo]:~$ tcpdump -i ng0
tcpdump: listening on ng0
10:09:20.164094 192.168.1.101 > 192.168.1.3: icmp: echo request
10:09:20.164111 192.168.1.3 > 192.168.1.101: icmp: echo reply
10:09:21.165665 192.168.1.101 > 192.168.1.3: icmp: echo request
10:09:21.165682 192.168.1.3 > 192.168.1.101: icmp: echo reply
10:09:26.173258 192.168.1.101 > 192.168.1.3: icmp: echo request
10:09:26.173276 192.168.1.3 > 192.168.1.101: icmp: echo reply
10:09:31.180864 192.168.1.101 > 192.168.1.3: icmp: echo request
10:09:31.180882 192.168.1.3 > 192.168.1.101: icmp: echo reply
etc

This is what I get when listening to the public interface:

I have replaced the public ip of the xp box with $XP$ and the public ip of
the mpd server with $MPD$ to protect their identities on the lists.

10:13:05.507078 $XP$.dsl.in-addr.zen.co.uk > $MPD$.dsl.in-addr.zen.co.uk:
gre [KSv1] ID:d4d6 S:149 ppp:
10:13:05.507233 $MPD$.dsl.in-addr.zen.co.uk > $XP$.dsl.in-addr.zen.co.uk:
gre [KSAv1] ID:c000 S:74 A:149 ppp:
10:13:06.508585 $XP$.dsl.in-addr.zen.co.uk > $MPD$.dsl.in-addr.zen.co.uk:
gre [KSv1] ID:d4d6 S:150 ppp:
10:13:07.007718 $MPD$.dsl.in-addr.zen.co.uk > $XP$.dsl.in-addr.zen.co.uk:
gre [KAv1] ID:c000 A:150 [|gre]
10:13:07.438692 $MPD$.dsl.in-addr.zen.co.uk.pptp >
$XP$.dsl.in-addr.zen.co.uk.3015: P 3213034689:3213034705(16) ack 781309220
win 58400: pptp CTRL_MSGTYPE=ECHORQ ID(5) (DF)
10:13:07.439050 $XP$.dsl.in-addr.zen.co.uk.3015 >
$MPD$.dsl.in-addr.zen.co.uk.pptp: P 1:21(20) ack 16 win 63952: pptp
CTRL_MSGTYPE=ECHORP ID(5) RESULT_CODE(1) ERR_CODE(0) (DF)
10:13:07.538639 $MPD$.dsl.in-addr.zen.co.uk.pptp >
$XP$.dsl.in-addr.zen.co.uk.3015: . ack 21 win 58400 (DF)
10:13:11.516195 $XP$.dsl.in-addr.zen.co.uk > $MPD$.dsl.in-addr.zen.co.uk:
gre [KSv1] ID:d4d6 S:151 ppp:
10:13:12.015955 $MPD$.dsl.in-addr.zen.co.uk > $XP$.dsl.in-addr.zen.co.uk:
gre [KAv1] ID:c000 A:151 [|gre]
10:13:16.523867 $XP$.dsl.in-addr.zen.co.uk > $MPD$.dsl.in-addr.zen.co.uk:
gre [KSv1] ID:d4d6 S:152 ppp:
10:13:16.524018 $MPD$.dsl.in-addr.zen.co.uk > $XP$.dsl.in-addr.zen.co.uk:
gre [KSAv1] ID:c000 S:75 A:152 ppp:
10:13:17.525379 $XP$.dsl.in-addr.zen.co.uk > $MPD$.dsl.in-addr.zen.co.uk:
gre [KSv1] ID:d4d6 S:153 ppp:
10:13:18.025044 $MPD$.dsl.in-addr.zen.co.uk > $XP$.dsl.in-addr.zen.co.uk:
gre [KAv1] ID:c000 A:153 [|gre]
10:13:22.533079 $XP$.dsl.in-addr.zen.co.uk > $MPD$.dsl.in-addr.zen.co.uk:
gre [KSv1] ID:d4d6 S:154 ppp:
10:13:23.032273 $MPD$.dsl.in-addr.zen.co.uk > $XP$.dsl.in-addr.zen.co.uk:
gre [KAv1] ID:c000 A:154 [|gre]
10:13:27.540633 $XP$.dsl.in-addr.zen.co.uk > $MPD$.dsl.in-addr.zen.co.uk:
gre [KSv1] ID:d4d6 S:155 ppp:
10:13:27.540786 $MPD$.dsl.in-addr.zen.co.uk > $XP$.dsl.in-addr.zen.co.uk:
gre [KSAv1] ID:c000 S:76 A:155 ppp:
10:13:28.542216 $XP$.dsl.in-addr.zen.co.uk > $MPD$.dsl.in-addr.zen.co.uk:
gre [KSv1] ID:d4d6 S:156 ppp:
10:13:29.041353 $MPD$.dsl.in-addr.zen.co.uk > $XP$.dsl.in-addr.zen.co.uk:
gre [KAv1] ID:c000 A:156 [|gre]

Notice the pptp ECHORQ ID(5) ... maybe that can help us in some way?

Thanks for any help you can give.


--
Dan Hardiker [dhardiker at eorigen.com]
ADAM Systems Engineer
eOrigen Ltd