FreeBSD and NMAP
dgerow at afflictions.org
Tue Apr 19 11:54:00 PDT 2005
Thus spake Dominic Marks (dom at helenmarks.co.uk) [19/04/05 07:18]:
: On Tuesday 19 April 2005 12:11, pck wrote:
: > Hi,
: > How can i hide from nmap that my OS is FreeBSD? Is this possible?
: # sysctl -ad | grep random_id
: net.inet.ip.random_id: Assign random ip_id values
: # echo 'net.inet.ip.random_id=1' >> /etc/sysctl.conf
That doesn't hide the OS. That just makes the IP ID field random.
One way to help:
echo "net.inet.tcp.drop_synfin=1' >> /etc/sysctl.conf
(Note that you need the "options TCP_DROP SYNFIN" line in your kernel
Other than that... randomize the packet fingerprint data. I know there's
been at least one daemon that did this on Linux, as well as a kernel patch
that did the same. But I'd ask: why? You're doing a significant amount of
work for very little in return.
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