-p
-sV
-sC
-O
-A
-T<0-5>
-oA
-sU
-Pn
-v
-vv
-d
-dd
--max-retries
-sS
), when running as privileged user (root or sudoer), otherwise it falls back to full TCP 3-way handshakes (-sT
) per default.port unreachable
is sent back.
BUT: Response may get dropped (firewalls, routers, ...) -> false positiveIn computer networking, port knocking is a method of externally opening ports on a firewall by generating a connection attempt on a set of prespecified closed ports.