/proc/sys/net/ipv4/tcp_syncookies: No such file or directory

[tcma]

I want to setup a firewall so I use KMyFirewall.
I
I choose all the default options (i.e. just click "next" and finally "finish" button.)

This is the KMyFirewall log:
Shutdown KMyFirewall... Done.
Starting firewall...
Loading needed modules... Done.
Create custom chains... Done.
Settup Rules in Table FILTER:
Create Rules for Chain: INPUT Done.
Create Rules for Chain: OUTPUT Done.
Create Rules for Chain: FORWARD Done.
Disable IP Forwarding. Done.
Enable Reverse Path Filtering Done.
Disable log_martians (logging). Done.
Enable Syn Cookies. Done.
Error: /tmp/kde-root/kmyfirewallADAhGa.tmp: line 78: /proc/sys/net/ipv4/tcp_syncookies: No such file or directory

Finished successfully

# ls -l /proc/sys/net
total 0
dr-xr-xr-x 6 root root 0 Feb 22 16:55 ipv4

The directory /proc/sys/net/ipv4 and its parent directory is read only.

KMyFirewall version: 0.9.6.2
Linux version 2.6.10-gentoo-r6

Because the final message is "Finished successfully", is the message
"Error: /tmp/kde-root/kmyfirewallADAhGa.tmp: line 78: /proc/sys/net/ipv4/tcp_syncookies: No such file or directory" a minor problem which can be ignored?
or it is a problem, then how to fix it?

[moocha]

It's not a problem as such and you can ignore it. It's caused by failing to compile in TCP Syncookies support. You most probably do want TCP syncookie support in your kernel. You'll find the corresponding option under Networking options in the kernel configuration. Read the help text there for more info.