Find all open ports using nmap

To find all open ports on a computer, run

nmap -P0 -vv -sS -ff -r -n -p 1-65535 IP_ADDR_HERE

1	nmap -P0 -vv -sS -ff -r -n -p 1-65535 IP_ADDR_HERE

-sS = SYN scan

if you only need to scan most common ports, use

nmap IP_ADDR_HERE

1	nmap IP_ADDR_HERE

Example

nmap list ports

To see open ports on your local computer, run

nmap localhost

1	nmap localhost

nmap -p 22 IP_ADDR	Scan a single port
nmap -p 1-100 IP_ADDR	Scan range of ports
nmap -p- IP_ADDR	Scan all 65535 ports
nmap -F IP_ADDR	Scan most popular 100 ports (fast scan)