your second command doesn't work!
After doing the echo command I did:
ipfwadm -F -a m 192.168.0.0/24 -D 0.0.0.0/0
and I got this:
[root@localhost /root]# ipfwadm -F -a m 192.168.0.0/24 -D 0.0.0.0/0
Unexpected argument `192.168.0.0/24'.
If this command worked with the original ipfwadm 2.3, please
submit a bug report to `email@example.com'. Note that you
now need to be root, even to list the chains (complain to Alan Cox).
The best way to do this is to submit the output of `/sbin/ipfwadm --version',
the command used to obtain this error, any previous ipfwadm
commands, and the output of `ipchains-save'.
Then try flushing all the rules `ipchains -F; ipchains -X',
setting the DEBUG_IPFWADM variable `export DEBUG_IPFWADM=1' or
`setenv DEBUG_IPFWADM 1' and rerunning the command(s) which
caused this error.
Ain't an expert on this, can you tell me more,