Houston, we have a problem.

This is out network configuration:

--> router <--Ether--> NetBSD_A <--PPP--> NetBSD_B <--Ether--> Win95

Here's a tcpdump output from NetBSD_B:

# tcpdump src or dst torakka
tcpdump: listening on le0
14:00:45.963003 arp who-has gw.jmp.fi tell torakka.jmp.fi
14:00:45.963172 arp reply gw.jmp.fi is-at 0:e0:29:5:43:63
14:00:45.963318 torakka.jmp.fi.1034 > www.merita.fi.www: S 11789484:11789484(0) win 8192 <mss 1460> (DF)
14:00:46.666003 www.merita.fi.www > torakka.jmp.fi.1034: S 95151290:95151290(0) ack 11789485 win 8760 <mss 4420> (DF)
14:00:46.666261 torakka.jmp.fi.1034 > www.merita.fi.www: . ack 1 win 8760 (DF)
14:00:46.670741 torakka.jmp.fi.1034 > www.merita.fi.www: P 1:188(187) ack 1 win 8760 (DF)
14:00:49.894990 torakka.jmp.fi.1034 > www.merita.fi.www: P 1:188(187) ack 1 win 8760 (DF)
14:00:50.616083 www.merita.fi.www > torakka.jmp.fi.1034: . ack 188 win 8573 (DF)
14:05:46.627321 arp who-has gw.jmp.fi tell torakka.jmp.fi
14:05:46.627480 arp reply gw.jmp.fi is-at 0:e0:29:5:43:63
14:05:46.627624 torakka.jmp.fi.1034 > www.merita.fi.www: R 11789672:11789672(0) win 0 (DF)

And here's a tcpdump output from NetBSD_A (notice the packets that never
show up on B):

# tcpdump src or dst torakka
tcpdump: listening on ep0
14:00:46.042109 torakka.jmp.fi.1034 > www.merita.fi.www: S 11789484:11789484(0) win 8192 <mss 1460> (DF)
14:00:46.594447 www.merita.fi.www > torakka.jmp.fi.1034: S 95151290:95151290(0) ack 11789485 win 8760 <mss 4420> (DF)
14:00:46.782118 torakka.jmp.fi.1034 > www.merita.fi.www: . ack 1 win 8760 (DF)
14:00:46.832405 torakka.jmp.fi.1034 > www.merita.fi.www: P 1:188(187) ack 1 win 8760 (DF)
14:00:47.229362 www.merita.fi.www > torakka.jmp.fi.1034: . 1:1461(1460) ack 188 win 8573 (DF)
14:00:47.323904 www.merita.fi.www > torakka.jmp.fi.1034: . 1461:2921(1460) ack 188 win 8573 (DF)
14:00:50.112215 torakka.jmp.fi.1034 > www.merita.fi.www: P 1:188(187) ack 1 win 8760 (DF)
14:00:50.200577 www.merita.fi.www > torakka.jmp.fi.1034: . 1:1461(1460) ack 188 win 8573 (DF)
14:00:50.486413 www.merita.fi.www > torakka.jmp.fi.1034: . ack 188 win 8573 (DF)
14:00:56.338890 www.merita.fi.www > torakka.jmp.fi.1034: . 1:1461(1460) ack 188 win 8573 (DF)
14:01:08.935904 www.merita.fi.www > torakka.jmp.fi.1034: . 1:1461(1460) ack 188 win 8573 (DF)
14:01:33.018088 www.merita.fi.www > torakka.jmp.fi.1034: . 1:1461(1460) ack 188 win 8573 (DF)
14:02:21.340368 www.merita.fi.www > torakka.jmp.fi.1034: . 1:1461(1460) ack 188 win 8573 (DF)
14:05:46.693265 torakka.jmp.fi.1034 > www.merita.fi.www: R 11789672:11789672(0) win 0 (DF)

It seems that some packets get lost in the PPP link.  The same thing happens
with two similar subnets, hanging off NetBSD_A with a PPP link.

The MTU of the PPP link is set to 576 - after having similar problems a few
months ago.  Some people are pretty annoyed because they can't connect to
their bank at all...  Even stanger, NetBSD_B can connect to the same WWW
server just fine.

Ideas?

  -jm the problem finder


-- 

                       1503 kHz @ 22:30 EET DST Mon-Fri

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