Patch to nmap 2.12 to do another type of stealth scan similar to the xmas scan, which is not currently logged by iplog and some IDS software.
You can download it from the following link: https://packetstormsecurity.com/files/download/17159/nmap-2.12-vek.patch
Source: https://packetstormsecurity.com/files/17159/Nmap-2.12-Stealth-Xmas-Patch.html