"res17fyz" <res17fyz@verizon.net> (who is actually jcline@ieee.org):
> Anders Dinsen anders@dinsen.net :
> >On Sun, 2 Jun 2002 jcline@ieee.org (aka res17fyz) wrote:
> >> The problem is that large PC transfers hang after ~1-2 megs.
> >> i.e. an ftp to ftp.netbsd.org, or web video, etc, will stop
> >> packet flow.  At this point I can kill the PC app and normal
> >> ftp or web browsing works ok, however the transfer is toast.
> >> What's the difference between a high bandwidth connection
> >> and a slow one?  The DSL link is 768k downstream and 384k up
> >> (supposedly though luckily I'm only 2 blocks from the CO so
> >> it should be max rate).
>
> >Does it work without the NetBSD box? I have seen ADSL modems do this with
> >bad lines, which may (strangely) occur when the CO is located close to
the
> >CPE.
>
> Yes, it works without the NetBSD gateway in the middle, i.e.
> --[dsl modem] -- eth -- [ hub ] -- [ pc ]
>
> I can ftp fine (for ex. archive.progeny.com, 62kb/s download) and
> view high bandwidth streams (for ex. yahoo news).
> Also, I can ftp from the NetBSD gateway itself, i.e. the following
> works fine too, in fact I installed via network.
> --[dsl modem] -- eth tlp0 -- [netbsd]
>
> So it seems there's something along the netbsd--rtk0--PC path that is
> the problem.
>
> Any ideas?  I suppose I need to test the rtk0 path, perhaps enable ftp on
> netbsd and try to stress LAN-side data flow.

I have further narrowed the problem..
First, a second PC (win9x) on the LAN side has the same problem.  As much
as I like to usually blame the win9x o/s it seems innocent this time.

Second, I set the netbsd gateway up to run httpd and have transferred 20+
meg
files from the rtk0 interface to the PC.  So this rules out the rtk0 or PC
as being
the bottleneck.  The problem appears to be the dataflow between the WAN
side tlp0 and the LAN side rtk0.

Here's some additional info in case it helps..
% ipnat -s
mapped   in          117067   out   79870
added      6227     expired   6190
no memory           0             bad nat 0
inuse                    37
rules                    3
wilds                   0

I do find it interesting that there's a dozen nat 'active sessions' after a
while
when the PC is relatively idle..  Most of these are mapped to the ISP's dns
server(s).  Though, since the problem occurs in the middle of transfer,
I'd assume NAT isn't the problem since the connection is already mapped
(amateur assumption).  If I open an ftp connection on win9x and use
ipmon -a on the gateway, then I see 'STATE:NEW' for every 'ls' command
I use in ftp, on a new port, and if I get a large file, the ftp session dies
due
to the data problem minutes before the NAT session expires.

Low bandwidth tasks still seem fine, such as web surfing, or network
gaming, or sending desperate emails to unix mailinglists..

Sorry if the change in email address has confused anyone.