====== Ubuntu - nmap - Scan remote hosts using TCP ACK (PA) and TCP Syn (PS) ======
Sometimes packet filtering firewalls block standard ICMP ping requests.
In that case, use TCP ACK and TCP Syn methods to scan remote hosts.
sudo nmap -PS 192.168.1.69
result:
Starting Nmap 6.40 ( http://nmap.org ) at 2016-07-08 01:22 BST
Nmap scan report for peter-laptop-1 (192.168.1.69)
Host is up (0.0000060s latency).
Not shown: 997 closed ports
PORT STATE SERVICE
80/tcp open http
139/tcp open netbios-ssn
445/tcp open microsoft-ds
Nmap done: 1 IP address (1 host up) scanned in 2.44 seconds