On Sat, 2003-08-23 at 07:56, E Lofstad wrote:
> I can not pull up the Slashdot or a couple other OSDN sites (like
> newsforge, linux.com).  I don't know what has changed.  I'm running
> Debian Sarge, but I don't think anything with the TCP stuff has
> changed in a while.  After the initial response from slashdot, there
> are no more packets.  Any thoughts?

Heh, this looks like behavior caused by my favorite feature of the
kernel, but it could be something else.  One of the most common causes
of sites disappearing from the 'Net is the use of TCP ECN (Explicit
Congestion Notification).  This uses a previously reserved field in the
TCP header, so old routers that expect the field to be set to zero can
do things like drop packets or reset the connection.

I usually try to have it enabled on my system since it is supposed to
help the Internet handle congestion more gracefully, but after a few
days I'll tend to notice that I can't get to one site or another, so I
have to turn it off.

To see if it's enabled on your system

  cat /proc/sys/net/ipv4/tcp_ecn

To disable it (which is the default these days)

  echo 0 > /proc/sys/net/ipv4/tcp_ecn

This feature may have been enabled in your /etc/sysctl.conf file, so
you'll want to check there to make sure it doesn't get re-enabled on
reboot..

It's possible that the problem is on the other end, in which case you'd
need to contact someone somewhere (but I don't know where, exactly). 
Or, I might be completely wrong, and some completely separate issue
might be causing the problem.

-- 
 _  _  _  _ _  ___    _ _  _  ___ _ _  __   #define EBEFOREI /* Invalid
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[ Mike Hicks | http://umn.edu/~hick0088/ | mailto:hick0088 at tc.umn.edu ]
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