How can I evade IDS/IPS/firewalls?
The Nmap man page has a section on evasion. The important thing to note is that firewall and IDS vendors are also racing to close any potential holes in their products. Nmap implements some techniques (fragmentation, slow scanning, low source port) that have worked in the past, but most of these will not help against a modern firewall or IDS.
- Remember that scanning a system that you do not own may be illegal.