Problems connecting to machines behind firewalls
caker
Linode Staff
If you are having problems connecting to remote machines from inside your Linode, and the remote machine doesn't return pings, it might be behind an old firewall that doesn't do ECN. Do this to turn it off:
echo 0 > /proc/sys/net/ipv4/tcp_ecn
You can add that to a startup script to disable ECN on boot.
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CONFIG_INET_ECN:
Explicit Congestion Notification (ECN) allows routers to notify
clients about network congestion, resulting in fewer dropped packets
and increased network performance. This option adds ECN support to
the Linux kernel, as well as a sysctl (/proc/sys/net/ipv4/tcp_ecn)
which allows ECN support to be disabled at runtime.
Note that, on the Internet, there are many broken firewalls which
refuse connections from ECN-enabled machines, and it may be a while
before these firewalls are fixed. Until then, to access a site behind
such a firewall (some of which are major sites, at the time of this
writing) you will have to disable this option, either by saying N now
or by using the sysctl.
Shot out to David Coulson for some help - thanks!
-Chris
6 Replies
I am not trying to blast you guys with all the stupid quesions at once.
bootcamp
thanks
It is up to you to install your own firewall.
Adam
If you need help setting up a firewall, come to the IRC chan, I am sure someone there can help you.
Adam
