NAT connection only half working

[Erik Rossen]

On Sat, Nov 29, 2003 at 06:16:48PM -0700, Andrew Nelson wrote:
> Well then I figure something must be muffed up with my ipables rule.
> Just to make sure I plug my laptop into the same switch as the node
> atom01 is plugged into.  I then set the laptop to boot via dhcp and
> see if I experience the same problems.  This is the weird part.  I
> have no problems with the laptop.  Ping works, wget works and apt-get
> update works.

So it sounds like your network between a given atom and the Internet
should work.

> So there is my problem.  If anyone has any ideas what I could do to
> fix or trouble shoot this problem please let me know.  I will be
> eternally gratefull.

Some things that I would try:

1. Use a different source for APT, preferably a local one.  You may have
been trying to use a server that was particularly busy or your ISP has a
transparent caching proxy that was messing up the downloads.  Debian's
servers have been particularly stressed this last week.  Install
apt-proxy on mantispid - it is a *huge* time-saver.


If that does not fix the problem, try

2. Turn off ECN on atom01 - some old routers (and maybe even your ADSL
modem) think that the ECN option of TCP packets is a sign of a bad
packet.  You can turn off ECN by adding the following line to
/etc/sysctl.conf in the FAI nfsroot:
   net/ipv4/tcp_ecn=0
or manually typing:
   echo 0 > /proc/sys/net/ipv4/tcp_ecn


If that does not fix the problem, try

3. Change the cables that connect atom01 to the switch.  I have seen
partially-broken cables exhibit some really strange intermittant
behavior.


If that does not fix the problem,

4. Try a different port on the switch.


Do not forget to let us know what the solution was in the end.

-- 
Erik Rossen                          ^    OpenPGP key: 2935D0B9
rossen at freesurf.ch                  /e\   "Use GnuPG, see the
http://people.linux-gull.ch/rossen  ---    black helicopters."