On Sunday 23 March 2008 03:16:16 Dan Cowsill wrote:
>  I
> also understand that its maximum is something on the order of 65000
> simultaneous connections.

That's a significant understatement.
The default limit is based on how much RAM you have, and is set very
conservatively.
/proc/sys/net/ipv4/netfilter/ip_conntrack_max sets how many connections you
can track.

You should also
drop /proc/sys/net/ipv4/netfilter/ip_conntrack_tcp_timeout_established
significantly. Connections can hang around for weeks, unless properly closed.

On the production linux firewalls I maintain they were happily handling
~50-60k connections until I dropped ip_conntrack_tcp_timeout_established to
432000 seconds when the conntrack table dropped to ~30k. I could drop it a
lot lower, but the machines cope with absolutely no issues.

Personally, I'd drop ip_conntrack_tcp_timeout_established to about a day, or
even less, as connections won't time out if traffic continues to pass.

--
Mike Williams
--
gentoo-user@(protected)