I can't identity my Linux Mint 17 machine on my home network. I use

nmap -O -v

However, I get the following output (below). I am just learning nmap, so I don't know what all of the output means. I don't have firewall up on Mint (well, not during testing). I checked ifconfig and my router's assigned dynamic IP: they are (it is a funky router by Bell with fancy web GUI). I have Samba running, which is (I guess) port 445. I don't yet understand what netbios is, but I am reading about it. I know that OS detection works better when more ports are open, but maybe those 2 are too generic?

I am not sure, what else I need to provide for a better question. Update: Sorry, the questions is: why can't I detect OS correctly even though this is a fairly standard install?

I am happy to submit a report to Nmap about it not being able to detect the OS, but before that I want to make sure it's not me that's the problem. Thank you!

Starting Nmap 6.00 ( http://nmap.org ) at 2015-08-19 19:47 EDT
Initiating ARP Ping Scan at 19:47
Scanning [1 port]
Completed ARP Ping Scan at 19:47, 0.10s elapsed (1 total hosts)
Initiating Parallel DNS resolution of 1 host. at 19:47
Completed Parallel DNS resolution of 1 host. at 19:47, 0.01s elapsed
Initiating SYN Stealth Scan at 19:47
Scanning [1000 ports]
Discovered open port 139/tcp on
Discovered open port 445/tcp on
Completed SYN Stealth Scan at 19:47, 0.60s elapsed (1000 total ports)
Initiating OS detection (try #1) against
Retrying OS detection (try #2) against
Retrying OS detection (try #3) against
Retrying OS detection (try #4) against
Retrying OS detection (try #5) against
Nmap scan report for
Host is up (0.011s latency).
Not shown: 998 closed ports
139/tcp open  netbios-ssn
445/tcp open  microsoft-ds
MAC Address: 94:39:E5:BF:0D:3B (Hon Hai Precision Ind. Co.)
No exact OS matches for host (If you know what OS is running on it, see http://nmap.org/submit/ ).
TCP/IP fingerprint:

Uptime guess: 1.485 days (since Tue Aug 18 08:09:06 2015)
Network Distance: 1 hop
TCP Sequence Prediction: Difficulty=263 (Good luck!)
IP ID Sequence Generation: All zeros

Read data files from: /usr/bin/../share/nmap
OS detection performed. Please report any incorrect results at http://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 32.14 seconds
           Raw packets sent: 1111 (52.918KB) | Rcvd: 1078 (46.650KB)
  • 1
    "No exact OS matches for host (If you know what OS is running on it, see nmap.org/submit )." You're prolly doing it fine (as long as your scanning the right host).
    – KDEx
    Commented Aug 20, 2015 at 0:42
  • Thanks @Morgoroth. Yeah, I double checked that this is the right machine in the router and with ifconfig. So, it should be right (I don't have that many on my network :)). I will submit this to nmap eventually, but it throws me off that this is a standard Linux distro with standard services running, which should give Nmap info to ID it. Commented Aug 20, 2015 at 1:09
  • I'm not clear about what your question is.
    – schroeder
    Commented Aug 20, 2015 at 3:59
  • 1
    you're running a really old version of nmap, so maybe it didn't have Mint's signature in 2012, and nmap uses a variety of factors to determine the OS, include packet signatures, which is likely being fiddled with by your Bell router
    – schroeder
    Commented Aug 20, 2015 at 4:04

2 Answers 2


As Morgoroth pointed out, nmap.org/submit is your friend in this case. However, you can also try

  • Using the --osscan-guess flag to more aggressively guess the OS (lower confidence interval)
  • Try a different type of scan (null, ack) using the -sN and -sA flags
  • Sometimes using the -A flag will give you something under "service info" that you can use to imply the OS.
  • However, be sure to use latest nmap version before submitting, since it is no good to submit signature already known in current signatures databases. Commented Aug 20, 2015 at 8:43
  • Thanks Nic Barker and @WhiteWinterWolf. I can't upvote the answer yet, but accepted it. I will try the suggestions and then submit a report to Nmap. Cheers. Commented Aug 20, 2015 at 12:35
  • 1
    Using -sN, -sA or other scan types will not help: OS detection uses only TCP and UDP probes, so you must use a scan type that can distinguish an open TCP port from a closed one. Usually -sSU is the best combination, but even with out -sU, Nmap will guess at a UDP port, hoping to hit an unused (closed) one. Commented Aug 20, 2015 at 20:08
  • @bonsaiviking thanks for the pointer, I wasn't fully aware of how OS scanning works.
    – Nic Barker
    Commented Aug 20, 2015 at 22:39

Nmap 6.00 was released in May 2012, so it cannot possibly have signatures for any Linux kernel later than 3.4. In the current database, your fingerprint matches exactly for "Linux 3.2 - 3.19". You can find the latest Nmap at https://nmap.org/download.html

  • Thank you! That makes perfect sense. So the problem is me in a sense that I am running an old nmap. I am running this on Raspberry Pi, which explains why it is old. I typically use Arch and Mint, so it did not occur to me to check the version. Thanks. I will update and try again. Sorry, I can't upvote and already accept the answer, however, I think this exactly answers why the problem is happening. Commented Aug 20, 2015 at 13:16
  • For what it's worth, I wasn't able to get a unique fingerprint on Linux Mint either, using 6.47.
    – Nic Barker
    Commented Aug 20, 2015 at 22:40
  • @NicBarker Nmap 6.47 is a year old, too. We just put out a series of BETA releases that are actually quite stable. We'll be doing another fingerprint update before the next major release, too. Nmap-announce mailing list will keep you in the loop: nmap.org/mailman/listinfo/announce Commented Aug 21, 2015 at 12:05
  • @bonsaiviking Ah, I didn't realise. Appreciate the info, I'll definitely check out the beta and the mailing list.
    – Nic Barker
    Commented Aug 22, 2015 at 0:30

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