just curious, but why 9 ircds?

So far my results seem to show that a tcp_keepalive_time of 1650 causes SSH timeouts, but 1500 does not. I'm trying to narrow it down a little further.

Just for reference, the bridging that occurs on the hosts essentially dumps Ethernet frames onto the local network (the switch) -- the host's don't have any concept of TCP connections between your Linodes and the world. It's just layer-2 bridging.

There is a known issue that affects a few of the hosts, including host5 and host6. Apparently, when someone joins the bridge it blips the bridge long enough to disturb at least some of the people already on the bridge.

I'm scheduling a reboot for host6 and will test the fix. If everything goes well, I'll schedule reboots for the rest of the hosts that are affected as well.

Now, as far as idle ssh connections being timed out, you can try this (worked for me):

# send keepalive packets every 5 minutes
echo 300 > /proc/sys/net/ipv4/tcp_keepalive_time

#I also added this to my /etc/sshd/sshd_config:
KeepAlive yes
ClientAliveInterval 10

/etc/init.d/ssh restart

logout and reconnect. My idle ssh session remained connected over night.

-Chris

$x9=more money
$x1=less money

I find it odd that idle ssh sessions are dying.

I generally keep ssh sessions open from at least 2 systems in seperate locations (ie, home/work) to my linode and use screen to jump back and forth.

using putty or openssh as the client i have no real disconnect issues in the long-term. I believe my putty session from an XP system has been connected for about 2 weeks now.. and it sits idle for hours if not days at the time.

-E

OK, I've narrowed it down as far as I am going to go; the magic number is between 1600 and 1700.

If you set your /proc/sys/net/ipv4/tcp_keepalive_time value to 1600, your (otherwise not keep-alived) SSH sessions will not timeout.

If you set your /proc/sys/net/ipv4/tcp_keepalive_time value to 1700, your (otherwise not keep-alived) SSH sessions will timeout after about half an hour.

Anyone who is not experiencing SSH timeouts probably either already has their tcp_keepalive_time value set low enough, or has SSH set to do keepalives.

I recommend using the tcp_keepalive_time value rather than SSH keepalives, because the former will work for all kinds of network connections, the latter only for SSH.

Ok, but how do we set tcp_keepalive_time?

-Ashen

echo VALUE > /proc/sys/net/ipv4/tcp_keepalive_time

Put this an an rc startup file (such as /etc/rc.d/rc.local) to effect this setting on every boot.

While that will work just fine, the canonical Linux method is to use /etc/sysctl.conf, adding a line like:

net.ipv4.tcp_keepalive = 1500

See sysctl.conf(5) and sysctl(8) for details.

_________________
The irony is that Bill Gates claims to be making a stable operating system and Linus Torvalds claims to be trying to take over the world.
-- seen on the net