Nmap also supports a number of performance and reliability features such as dynamic delay time calculations, packet timeout and retransmission, parallel port scanning, detection of down hosts via parallel pings. Increases the verbosity level, causing Nmap to print more information. Nmap supports Vanilla TCP connect() scanning, TCP SYN (half open) scanning, TCP FIN, Xmas, or NULL (stealth) scanning, TCP ftp proxy (bounce attack) scanning, SYN/FIN scanning using IP fragments (bypasses some packet filters), TCP ACK and Window scanning, UDP raw ICMP port unreachable scanning, ICMP scanning (ping-sweep), TCP Ping scanning, Direct (non portmapper) RPC scanning, Remote OS Identification by TCP/IP Fingerprinting, and Reverse-ident scanning. Network exploration tool and security / port scanner. Not to mention the fact that you may want to scan different protocols (UDP, TCP, ICMP, etc.). In some cases, bypassing firewalls may be required. Sometimes you need speed, other times you may need stealth. It can be used to identify live hosts, scan TCP and UDP open ports, detect firewalls, get versions. Now that you have gathered some IP addresses from your subdomain scanning it is time to scan those addresses.

Nmap is a utility for port scanning large networks, although it works fine for single hosts. Nmap is probably the most used port scanner in the world. Nmap Port Scanner 7.91 Nmap Port Scanner 7.91 Posted Authored by Fyodor | Site

Zenmap port scanner