After reboot debian box ignore sysctl.conf values
/etc/init.d/procps.sh comes too early in the boot process to apply a lot of sysctl's. As it runs before networking modules are loaded and filesystems are mounted, there are quite a lot of commonly-used sysctl's which are simply ignored on boot and produce errors to the console.
All documentation on the net referring to changing certain settings in /etc/sysctl.conf such as
net.ipv4.netfilter.ip_conntrack_max is wrong for Ubuntu & Debian.
Finally, "It seems to me it is a Debian Squeeze bug, see here for an example and workaround: http://wiki.debian.org/BridgeNetworkConnections
In the latter case, the procps init script should take care of loading them during boot. However, on Squeeze it does not, and you need to restart it from /etc/rc.local (or similar):
# /etc/rc.local # Load kernel variables from /etc/sysctl.d /etc/init.d/procps restart exit 0
Check if there is a file in /etc/sysctl.d with your parameter. These files override the /etc/sysctl.conf file...
If you use ufw (uncomplicated firewall) you really need to change the values in
/etc/ufw/sysctl.conf as the configuration here overrides