If a port is open, the operating system completes the TCP three-way handshake, and the port scanner immediately closes the connection to avoid performing a Denial-of-service attack.
Ako je port otvoren, operativni sistem završava TCP trostruko rukovanje, i skener portova odmah zatvara konekciju kako bi izbegao izvršavanje Denial-of-service napada (Uskraćivanje servisa).