using --string

[Ostdeutschland@gmx.de]

Hi

I've some problems using the --string option...
I would like to use something like:

iptables -A INPUT -i ppp0 -p tcp -m string --string ?cmd.exe? -j DROP

but it results in:

[root@router logs]# iptables -A INPUT -i ppp0 -p tcp -m string --string
?cmd.exe? -j DROP
iptables v1.2.4: Couldn't load match
`string':/lib/iptables/libipt_string.so: cannot open shared object file: No
such file or directory

[root@router logs]# locate libipt_strings.so
[root@router logs]#

Where can I get this module? Or do I simply need to enable something in the
kernel config?

Bye