> 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
This is exactly what portsentry is designed to do. Can't tell if a port is hit without first binding to it. I have placed portsentry on other machines than the firewall for just this sort of information. A better solution on a firewall is to turn on logging for specific ports or rules that you are interested in. > 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. What ports exactly are still listening that aren't getting allowed through? > 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. logcheck - not really syslog should be sent inside either via syslog or msyslog (in ports) portsentry - nope (see above) snort - i 'spose (no harm per say) tripwire - definately > any thoughts? > > thanks again > > redmond Hope this helps. -- Scott A. Moberly [EMAIL PROTECTED] "BASIC is the Computer Science equivalent of `Scientific Creationism'." To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-questions" in the body of the message
