Securing FreeBSD

G D McKee freebsd at
Thu May 15 10:58:50 PDT 2003

Hi all

I am trying to secure my freebsd box and avoid giving to much info away to port scans.

I have found some site relating to this and have put the following lines in /etc/sysctl.conf


and added these to the firewall:

options         RANDOM_IP_ID
options         TCP_DROP_SYNFIN         #drop TCP packets with SYN+FIN

Can someone explain to me why the TCP_DROP_SYNFIN option breaks web access?  It doesn't seem to have made any changes that I have noticed.  I can't find any docs regarding this to explain what it might break.  Does anyone know any other variables to add to make me more secure?

Thanks in advance


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