Network Mapping -> Identify Live Hosts -> Nmap
"Nmap ("Network Mapper") is a free and open source (license) utility for network discovery and security auditing. Many systems and network administrators also find it useful for tasks such as network inventory, managing service upgrade schedules, and monitoring host or service uptime. Nmap uses raw IP packets in novel ways to determine what hosts are available on the network, what services (application name and version) those hosts are offering, what operating systems (and OS versions) they are running, what type of packet filters/firewalls are in use, and dozens of other characteristics. It was designed to rapidly scan large networks, but works fine against single hosts. Nmap runs on all major computer operating systems, and official binary packages are available for Linux, Windows, and Mac OS X."
I couldn't write it better (source: nmap.org) :-) The tool has tons of options, worth to play around with it. This is the de-facto standard port scanning utility. That's all about it, there are lot of examples, and usage guide on their webpage, even in Hungarian. Here are two examples:
Usage: nmap [Scan Type(s)] [Options] {target specification}
TARGET SPECIFICATION:
Can pass hostnames, IP addresses, networks, etc.
Ex: scanme.nmap.org, microsoft.com/24, 192.168.0.1; 10.0.0-255.1-254
-iL <inputfilename>: Input from list of hosts/networks
-iR <num hosts>: Choose random targets
--exclude <host1[,host2][,host3],...>: Exclude hosts/networks
--excludefile <exclude_file>: Exclude list from file
HOST DISCOVERY:
-sL: List Scan - simply list targets to scan
-sn: Ping Scan - disable port scan
-Pn: Treat all hosts as online -- skip host discovery
-PS/PA/PU/PY[portlist]: TCP SYN/ACK, UDP or SCTP discovery to given ports
-PE/PP/PM: ICMP echo, timestamp, and netmask request discovery probes
-PO[protocol list]: IP Protocol Ping
-n/-R: Never do DNS resolution/Always resolve [default: sometimes]
--dns-servers <serv1[,serv2],...>: Specify custom DNS servers
--system-dns: Use OS's DNS resolver
--traceroute: Trace hop path to each host
SCAN TECHNIQUES:
-sS/sT/sA/sW/sM: TCP SYN/Connect()/ACK/Window/Maimon scans
-sU: UDP Scan
-sN/sF/sX: TCP Null, FIN, and Xmas scans
--scanflags <flags>: Customize TCP scan flags
-sI <zombie host[:probeport]>: Idle scan
-sY/sZ: SCTP INIT/COOKIE-ECHO scans
-sO: IP protocol scan
-b <FTP relay host>: FTP bounce scan
PORT SPECIFICATION AND SCAN ORDER:
-p <port ranges>: Only scan specified ports
Ex: -p22; -p1-65535; -p U:53,111,137,T:21-25,80,139,8080,S:9
-F: Fast mode - Scan fewer ports than the default scan
-r: Scan ports consecutively - don't randomize
--top-ports <number>: Scan <number> most common ports
--port-ratio <ratio>: Scan ports more common than <ratio>
SERVICE/VERSION DETECTION:
-sV: Probe open ports to determine service/version info
--version-intensity <level>: Set from 0 (light) to 9 (try all probes)
--version-light: Limit to most likely probes (intensity 2)
--version-all: Try every single probe (intensity 9)
--version-trace: Show detailed version scan activity (for debugging)
SCRIPT SCAN:
-sC: equivalent to --script=default
--script=<Lua scripts>: <Lua scripts> is a comma separated list of
directories, script-files or script-categories
--script-args=<n1=v1,[n2=v2,...]>: provide arguments to scripts
--script-trace: Show all data sent and received
--script-updatedb: Update the script database.
OS DETECTION:
-O: Enable OS detection
--osscan-limit: Limit OS detection to promising targets
--osscan-guess: Guess OS more aggressively
TIMING AND PERFORMANCE:
Options which take <time> are in milliseconds, unless you append 's'
(seconds), 'm' (minutes), or 'h' (hours) to the value (e.g. 30m).
-T<0-5>: Set timing template (higher is faster)
--min-hostgroup/max-hostgroup <size>: Parallel host scan group sizes
--min-parallelism/max-parallelism <numprobes>: Probe parallelization
--min-rtt-timeout/max-rtt-timeout/initial-rtt-timeout <time>: Specifies
probe round trip time.
--max-retries <tries>: Caps number of port scan probe retransmissions.
--host-timeout <time>: Give up on target after this long
--scan-delay/--max-scan-delay <time>: Adjust delay between probes
--min-rate <number>: Send packets no slower than <number> per second
--max-rate <number>: Send packets no faster than <number> per second
FIREWALL/IDS EVASION AND SPOOFING:
-f; --mtu <val>: fragment packets (optionally w/given MTU)
-D <decoy1,decoy2[,ME],...>: Cloak a scan with decoys
-S <IP_Address>: Spoof source address
-e <iface>: Use specified interface
-g/--source-port <portnum>: Use given port number
--data-length <num>: Append random data to sent packets
--ip-options <options>: Send packets with specified ip options
--ttl <val>: Set IP time-to-live field
--spoof-mac <mac address/prefix/vendor name>: Spoof your MAC address
--badsum: Send packets with a bogus TCP/UDP/SCTP checksum
--adler32: Use deprecated Adler32 instead of CRC32C for SCTP checksums
OUTPUT:
-oN/-oX/-oS/-oG <file>: Output scan in normal, XML, s|<rIpt kIddi3,
and Grepable format, respectively, to the given filename.
-oA <basename>: Output in the three major formats at once
-v: Increase verbosity level (use -vv or more for greater effect)
-d: Increase debugging level (use -dd or more for greater effect)
--reason: Display the reason a port is in a particular state
--open: Only show open (or possibly open) ports
--packet-trace: Show all packets sent and received
--iflist: Print host interfaces and routes (for debugging)
--log-errors: Log errors/warnings to the normal-format output file
--append-output: Append to rather than clobber specified output files
--resume <filename>: Resume an aborted scan
--stylesheet <path/URL>: XSL stylesheet to transform XML output to HTML
--webxml: Reference stylesheet from Nmap.Org for more portable XML
--no-stylesheet: Prevent associating of XSL stylesheet w/XML output
MISC:
-6: Enable IPv6 scanning
-A: Enables OS detection and Version detection, Script scanning and Traceroute
--datadir <dirname>: Specify custom Nmap data file location
--send-eth/--send-ip: Send using raw ethernet frames or IP packets
--privileged: Assume that the user is fully privileged
--unprivileged: Assume the user lacks raw socket privileges
-V: Print version number
-h: Print this help summary page.
EXAMPLES:
nmap -v -A scanme.nmap.org
nmap -v -sn 192.168.0.0/16 10.0.0.0/8
nmap -v -iR 10000 -Pn -p 80
SEE THE MAN PAGE (http://nmap.org/book/man.html) FOR MORE OPTIONS AND EXAMPLES
root@bt:~# nmap -sP 192.168.183.0/24
Starting Nmap 5.35DC1 ( http://nmap.org ) at 2011-05-09 14:36 EDT
Nmap scan report for 192.168.183.1
Host is up (0.00049s latency).
MAC Address: 00:50:56:C0:00:08 (VMware)
Nmap scan report for 192.168.183.2
Host is up (0.00021s latency).
MAC Address: 00:50:56:FB:42:C6 (VMware)
Nmap scan report for 192.168.183.130
Host is up (0.00028s latency).
MAC Address: 00:0C:29:11:69:AF (VMware)
Nmap scan report for 192.168.183.131
Host is up.
Nmap scan report for 192.168.183.132
Host is up (0.00020s latency).
MAC Address: 00:0C:29:EF:E7:29 (VMware)
Nmap scan report for 192.168.183.254
Host is up (0.00026s latency).
MAC Address: 00:50:56:E0:08:18 (VMware)
Nmap done: 256 IP addresses (6 hosts up) scanned in 9.31 seconds
root@bt:~# nmap -sS -O 192.168.183.0/24
Starting Nmap 5.35DC1 ( http://nmap.org ) at 2011-05-09 14:42 EDT
Nmap scan report for 192.168.183.1
Host is up (0.00037s latency).
Not shown: 993 filtered ports
PORT STATE SERVICE
21/tcp open ftp
135/tcp open msrpc
139/tcp open netbios-ssn
445/tcp open microsoft-ds
912/tcp open unknown
2869/tcp open icslap
5357/tcp open unknown
MAC Address: 00:50:56:C0:00:08 (VMware)
Warning: OSScan results may be unreliable because we could not find at least 1 o
pen and 1 closed port
Device type: general purpose
Running: Microsoft Windows Vista|2008|7
OS details: Microsoft Windows Vista SP0 or SP1, Server 2008 SP1, or Windows 7
Network Distance: 1 hop
Nmap scan report for 192.168.183.2
Host is up (0.057s latency).
Not shown: 984 closed ports
PORT STATE SERVICE
21/tcp open ftp
135/tcp open msrpc
445/tcp open microsoft-ds
514/tcp filtered shell
554/tcp open rtsp
912/tcp open unknown
1025/tcp open NFS-or-IIS
1026/tcp open LSA-or-nterm
1027/tcp open IIS
1028/tcp open unknown
1054/tcp open unknown
2869/tcp open icslap
5357/tcp open unknown
6059/tcp open X11:59
10000/tcp open snet-sensor-mgmt
10243/tcp open unknown
MAC Address: 00:50:56:FB:42:C6 (VMware)
Device type: general purpose|webcam|storage-misc|printer
Running (JUST GUESSING) : Apple Mac OS X 10.5.X (94%), DVTel embedded (88%), Blu
eArc embedded (88%), Brother embedded (85%)
Aggressive OS guesses: Apple Mac OS X 10.5.5 (Leopard) (94%), DVTel DVT-9540DW n
etwork camera (88%), BlueArc Titan 2100 NAS device (88%), Brother HL-5170DN prin
ter (85%)
No exact OS matches for host (test conditions non-ideal).
Network Distance: 1 hop
Nmap scan report for 192.168.183.130
Host is up (0.0027s latency).
Not shown: 996 closed ports
PORT STATE SERVICE
135/tcp open msrpc
139/tcp open netbios-ssn
445/tcp open microsoft-ds
1025/tcp open NFS-or-IIS
MAC Address: 00:0C:29:11:69:AF (VMware)
Device type: general purpose
Running: Microsoft Windows 2003|XP
OS details: Microsoft Windows Server 2003 SP1 or SP2, Microsoft Windows XP SP2 o
r Server 2003 SP1 or SP2
Network Distance: 1 hop
Nmap scan report for 192.168.183.131
Host is up (0.000056s latency).
All 1000 scanned ports on 192.168.183.131 are closed
Too many fingerprints match this host to give specific OS details
Network Distance: 0 hops
Nmap scan report for 192.168.183.132
Host is up (0.00053s latency).
Not shown: 997 filtered ports
PORT STATE SERVICE
139/tcp open netbios-ssn
445/tcp open microsoft-ds
2869/tcp closed icslap
MAC Address: 00:0C:29:EF:E7:29 (VMware)
Device type: general purpose
Running: Microsoft Windows XP
OS details: Microsoft Windows XP SP3
Network Distance: 1 hop
Nmap scan report for 192.168.183.254
Host is up (0.00020s latency).
All 1000 scanned ports on 192.168.183.254 are filtered
MAC Address: 00:50:56:E0:08:18 (VMware)
Too many fingerprints match this host to give specific OS details
Network Distance: 1 hop
OS detection performed. Please report any incorrect results at http://nmap.org/s
ubmit/ .
Nmap done: 256 IP addresses (6 hosts up) scanned in 358.56 seconds
root@bt:~# nmap -sn 192.168.183.0/24
Starting Nmap 5.35DC1 ( http://nmap.org ) at 2011-05-09 14:57 EDT
Nmap scan report for 192.168.183.1
Host is up (0.00018s latency).
MAC Address: 00:50:56:C0:00:08 (VMware)
Nmap scan report for 192.168.183.2
Host is up (0.00014s latency).
MAC Address: 00:50:56:FB:42:C6 (VMware)
Nmap scan report for 192.168.183.130
Host is up (0.00028s latency).
MAC Address: 00:0C:29:11:69:AF (VMware)
Nmap scan report for 192.168.183.131
Host is up.
Nmap scan report for 192.168.183.132
Host is up (0.00034s latency).
MAC Address: 00:0C:29:EF:E7:29 (VMware)
Nmap scan report for 192.168.183.254
Host is up (0.00046s latency).
MAC Address: 00:50:56:E0:08:18 (VMware)
Nmap done: 256 IP addresses (6 hosts up) scanned in 3.09 seconds
Official website: http://nmap.org/
