Unfortunately, I did not find any hints in the FAQs or this mailing list. I wanted to check our company's DMZ security. Therefore I started Nessus 1.1.14 from a Linux host which is located outside the firewall. The port scanning output of Nmap made me suspicious. I ran this task a dozen times. Once Nmap found the open ports, the next time just the one or the other, etc. It was really an unpleasant experience. There was no difference between starting the port scan with the inbuilt version of Nessus and starting Nmap separately. My first solution approach was to install older versions of Nmap, without success. When I reduced the port range to 1-30 and 20-30, Nmap found more open ports in the 20-30 port range than in the 1-30 port range.
I guess that this might be a timeout problem. Has anybody any experiences with the 'perfect' settings to deliver proper port scan results and to optimize the testing duration for a test over slow connections. The system specifications follow: Thanks for any help. Christoph Baumgartner Attacker System: PIII / 1000 MHz, 256 MB RAM Linux Red Hat 7.2 Nessus 1.1.14 Nmap 2.54 BETA32 Attacker Connection: ADSL 256/64 (Kbit) Target System(s): 1 - 5 IPs (Firewall and Servers in the DMZ) Target Connection: 512 Kbit
