====== Ubuntu - nmap - Scan a Host to Detect a Firewall ====== Perform a scan on a remote host to detect if any packet filters or Firewall is used by host. sudo nmap -sA sharewiz.net result: Starting Nmap 6.40 ( http://nmap.org ) at 2016-07-08 00:28 BST Nmap scan report for 192.168.1.2 Host is up (0.0011s latency). All 1000 scanned ports on 192.168.1.2 are unfiltered MAC Address: 44:A8:42:34:16:49 (Unknown) Nmap done: 1 IP address (1 host up) scanned in 90.32 seconds ---- ===== Results from another machine ===== result: Starting Nmap 6.40 ( http://nmap.org ) at 2016-07-08 00:31 BST Nmap scan report for sharewiz.net (5.42.134.35) Host is up (0.045s latency). rDNS record for 5.42.134.35: bbdp5.42.134.35.network.sure.com All 1000 scanned ports on sharewiz.net (5.42.134.35) are unfiltered (919) or filtered (81) Nmap done: 1 IP address (1 host up) scanned in 2.51 seconds