hi

if i enter below command i am getting o/p very late say 30 seconds it will take.

nmap -O 10.106.99.124

i want os information within 3 secs is there any option

Try adding "-P0"? Else give nmap as much verbose / debug output switches as possible and show us the output.

Hi unSpawn

my output

nmap -O 10.106.9.1

Starting Nmap 6.40 ( http://nmap.org ) at 2014-01-04 18:57 IST
Nmap scan report for 10.106.9.1
Host is up (0.0017s latency).
Not shown: 999 closed ports
PORT STATE SERVICE
23/tcp open telnet
Device type: switch
Running: Cisco IOS 12.X
OS CPE: cpe:/h:cisco:catalyst_1900 cpe:/h:cisco:catalyst_2820 cpe:/h:cisco:catalyst_2960 cpe:/h:cisco:catalyst_3560 cpe:/h:cisco:catalyst_4500 cpe:/h:cisco:catalyst_6513 cpe:/o:cisco:ios:12.2
OS details: Cisco Catalyst 1900, 2820, 2960, 3560, 3750, 4500, or 6513 switch (IOS 12.2)

OS detection performed. Please report any incorrect results at http://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 2.37 seconds


nmap -p0 10.106.9.1

Starting Nmap 6.40 ( http://nmap.org ) at 2014-01-04 18:58 IST
Nmap scan report for 10.106.9.1
Host is up (0.00071s latency).
PORT STATE SERVICE
0/tcp closed unknown

Nmap done: 1 IP address (1 host up) scanned in 0.28 seconds

nmap -Op0 10.106.9.1
Unknown argument to -O.
QUITTING!

i want o/p in below 1 second ..because i am checking more 5k ips so is it possible?

...so it isn't really "very late say 30 seconds it will take" slow.


I said add the switch, not mutilate nmaps command line arguments!


Depends on your network, devices and such. See http://www.professormesser.com/nmap/how-to-supercharge-your-nmap-scans/ and maybe Zmap, though in the case of the latter if I find you (even mistakingly) scanning the while Internet due to you not reading the documentation well enough to understand it there'll seriously be hell to pay.