Scan using TCP connect

This is the command to scan using the TCP connect option. If a user does not have raw packet privileges, this is the command they will use:

nmap -sT 192.168.0.9

Privileged access is necessary to perform the default SYN scans. If privileges are not sufficient, a TCP connect scan will be used. A TCP connect scan needs a full TCP connection to be established, and is known to be a slower scan than SYN scans. Disregarding discovery is often required as many firewalls or hosts will not answer to ping, so it could be missed, unless you choose the -Pn parameter. Of course, this can make the scan times much longer as you could end up sending scan probes to hosts that are not even there.