hi all

 i have an ipf/ipnat gateway machine protecting an internal network of - so far one, 
hopefully 2 or more - computers.
 the first thing i did after i observed that i have my setup successfully nat'ing, was 
to try to portscan myself from an outside machine, using nmap.
 at first i thought something was up, and that my ipf.rules were being ignored, 
because when i ran
 
 nmap -sS -v -O 

 on my the public ip of my internal host - which was aliased to the external nic of my 
gateway box - it showed that a huge amount of tcp and udp ports were open. i could 
copy the nmap results, but they're long, and suffice it to say ports i thought were 
closed or inactive were shown as open.
 
 after discussing it with the -security listserv, and running a 'sockstat' on the 
gateway box, it turns out that portsentry was indeed listening on the great majority 
of ports that the nmap showed to be open. when i turn portsentry off and run nmap 
again on my setup, it only shows ports that i specially allow open in my ipf/ipnat 
rules like 80,22, etc.
 
 my question is: first if anyone knows how to get portsentry to not broadcast the fact 
that it's listening on a wide variety ports when the host is being portscanned. i 
checked the portsentry.conf file, there didn't seem to be an option for this. also - i 
have
 
 block return-rst in log quick on xl0 proto tcp from any to any
 
 in my ipf.rules, so i thought that any ports not be nat'd would show up in portscans 
as not listening. not sure why this isn't working.
 
 also, i had wanted to run logcheck, portsentry, and snort or tripwire on my ipf/ipnat 
gateway box. is this a good combination of apps? as of now, i have portsentry turned 
off, but would like to use it or an app that performs the same function.
 
 any thoughts?
 
 thanks again

redmond

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