added fast scan for nmap

pages/common/nmap.md

@@ -9,3 +9,11 @@
 - discover hosts in the 192.168.0.X area (no port scan)
 
 `nmap -sn {{192.168.0.1/24}}`
+
+- faster scan of a single host (scans for common ports)
+
+`nmap -F {{192.168.0.1}}`
+
+- faster scan of a subnet (scans for common ports)
+
+`nmap -F {{192.168.0.1/24}}`