Re: Unable to open various sites.

[Alan Shutko <ats@acm.org>]

"Scott E. Graves" <scottg@lintuit.com> writes:

> I have been unable to connect to various web sites from one Debian machine on 
> our network. It seems that when attemplting to connect to sites, such as 
> www.dogpile.com, the user is receiving connection refused. All machines are 
> identical and no firewalling rules have been enabled. 

Try 

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

If that cures your problem, you've run into sites with firewalls which
block Explicit Congestion Notification, an experimental standard to
help detect congestion in TCP connections.  You can turn this off
permanently by

* Recompiling your kernel with TCP Explicit Congestion Notification support
  (CONFIG_INET_ECN) off, or

* Adding net.ipv4.tcp_ecn = 0 to your /etc/sysctl.conf.

-- 
Alan Shutko <ats@acm.org> - In a variety of flavors!
Oh, Aunty Em, it's so good to be home!