Does an intense scan without checking to see if targets are up first.
This can be useful when a target seems to ignore the usual host discovery probes.
sudo nmap -T4 -A -v -Pn 192.168.1.69
result:
Starting Nmap 6.40 ( http://nmap.org ) at 2016-07-08 01:54 BST NSE: Loaded 110 scripts for scanning. NSE: Script Pre-scanning. Initiating Parallel DNS resolution of 1 host. at 01:54 Completed Parallel DNS resolution of 1 host. at 01:54, 0.00s elapsed Initiating SYN Stealth Scan at 01:54 Scanning peter-laptop-1 (192.168.1.69) [1000 ports] Discovered open port 80/tcp on 192.168.1.69 Discovered open port 445/tcp on 192.168.1.69 Discovered open port 139/tcp on 192.168.1.69 Completed SYN Stealth Scan at 01:54, 2.00s elapsed (1000 total ports) Initiating Service scan at 01:54 Scanning 3 services on peter-laptop-1 (192.168.1.69) Completed Service scan at 01:55, 11.01s elapsed (3 services on 1 host) Initiating OS detection (try #1) against peter-laptop-1 (192.168.1.69) Retrying OS detection (try #2) against peter-laptop-1 (192.168.1.69) Retrying OS detection (try #3) against peter-laptop-1 (192.168.1.69) Retrying OS detection (try #4) against peter-laptop-1 (192.168.1.69) Retrying OS detection (try #5) against peter-laptop-1 (192.168.1.69) NSE: Script scanning 192.168.1.69. Initiating NSE at 01:55 Completed NSE at 01:55, 0.14s elapsed Nmap scan report for peter-laptop-1 (192.168.1.69) Host is up (0.0000080s latency). Not shown: 997 closed ports PORT STATE SERVICE VERSION 80/tcp open http nginx 1.4.6 (Ubuntu) |_http-methods: No Allow or Public header in OPTIONS response (status code 405) |_http-title: Site doesn't have a title (text/html). 139/tcp open netbios-ssn Samba smbd 3.X (workgroup: PETER-LAPTOP-1) 445/tcp open netbios-ssn Samba smbd 3.X (workgroup: PETER-LAPTOP-1) No exact OS matches for host (If you know what OS is running on it, see http://nmap.org/submit/ ). TCP/IP fingerprint: OS:SCAN(V=6.40%E=4%D=7/8%OT=80%CT=1%CU=44467%PV=Y%DS=0%DC=L%G=Y%TM=577EF9FD OS:%P=x86_64-pc-linux-gnu)SEQ(SP=106%GCD=1%ISR=107%TI=Z%CI=I%TS=8)OPS(O1=MF OS:FD7ST11NW7%O2=MFFD7ST11NW7%O3=MFFD7NNT11NW7%O4=MFFD7ST11NW7%O5=MFFD7ST11 OS:NW7%O6=MFFD7ST11)WIN(W1=AAAA%W2=AAAA%W3=AAAA%W4=AAAA%W5=AAAA%W6=AAAA)ECN OS:(R=Y%DF=Y%T=40%W=AAAA%O=MFFD7NNSNW7%CC=Y%Q=)T1(R=Y%DF=Y%T=40%S=O%A=S+%F= OS:AS%RD=0%Q=)T2(R=N)T3(R=N)T4(R=Y%DF=Y%T=40%W=0%S=A%A=Z%F=R%O=%RD=0%Q=)T5( OS:R=Y%DF=Y%T=40%W=0%S=Z%A=S+%F=AR%O=%RD=0%Q=)T6(R=Y%DF=Y%T=40%W=0%S=A%A=Z% OS:F=R%O=%RD=0%Q=)T7(R=Y%DF=Y%T=40%W=0%S=Z%A=S+%F=AR%O=%RD=0%Q=)U1(R=Y%DF=N OS:%T=40%IPL=164%UN=0%RIPL=G%RID=G%RIPCK=G%RUCK=G%RUD=G)IE(R=Y%DFI=N%T=40%C OS:D=S) Uptime guess: 0.243 days (since Thu Jul 7 20:05:36 2016) Network Distance: 0 hops TCP Sequence Prediction: Difficulty=262 (Good luck!) IP ID Sequence Generation: All zeros Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel Host script results: | nbstat: | NetBIOS name: PETER-LAPTOP-1, NetBIOS user: <unknown>, NetBIOS MAC: <unknown> | Names | PETER-LAPTOP-1<00> Flags: <unique><active> | PETER-LAPTOP-1<03> Flags: <unique><active> | PETER-LAPTOP-1<20> Flags: <unique><active> | \x01\x02__MSBROWSE__\x02<01> Flags: <group><active> | WORKGROUP<00> Flags: <group><active> | WORKGROUP<1d> Flags: <unique><active> |_ WORKGROUP<1e> Flags: <group><active> | smb-os-discovery: | OS: Windows 6.1 (Samba 4.3.9-Ubuntu) | Computer name: peter-laptop-1 | NetBIOS computer name: PETER-LAPTOP-1 | Domain name: | FQDN: peter-laptop-1 |_ System time: 2016-07-08T01:55:25+01:00 | smb-security-mode: | Account that was used for smb scripts: guest | User-level authentication | SMB Security: Challenge/response passwords supported |_ Message signing disabled (dangerous, but default) |_smbv2-enabled: Server supports SMBv2 protocol NSE: Script Post-scanning. Read data files from: /usr/bin/../share/nmap OS and Service detection performed. Please report any incorrect results at http://nmap.org/submit/ . Nmap done: 1 IP address (1 host up) scanned in 28.70 seconds Raw packets sent: 1275 (69.300KB) | Rcvd: 2599 (129.612KB)