After reboot debian box ignore sysctl.conf values

/etc/init.d/ 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:

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 /etc/sysctl.conf one.