Nmap er open source og gratis. Et værktøj til netværks opdagelse og sikkerheds revision. Kan køre på forskellige Linux systemer, Windows og Mac OS X. Nmap suite inkludere en avancered GUI (Zenmap) og command line (nmap). Nmap understøtter dusinvis af avancerede teknikker til at kortlægge netværket fyldt med IP-filtre, firewalls, routere og andre forhindringer. Dette omfatter mange port scanning mekanismer (både TCP & UDP), afsløring OS, version, afsløring, ping sweeps, og mere.

Nmap reference guide

Nmap Scriptiong Engine (NSE) er et af Nmaps mest powerfuld og felxible funktioner. Designet til at være alsidig, med følgende opgaver i tankerne: network discovery, mere sofistikeret versions detektion, vulnerability detektion, backdoor detection, vulnerability exploitation.

Download Nmap

Skriver du nmap I commad line vil du se de forskellige muligheder der er i Nmap.

C:\Program Files (x86)\Nmap>nmap

Nmap 7.40 ( https://nmap.org )

Usage: nmap [Scan Type(s)] [Options] {target specification}


Can pass hostnames, IP addresses, networks, etc.

Ex: scanme.nmap.org, microsoft.com/24,; 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


-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


-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


-sO: IP protocol scan

-b <FTP relay host>: FTP bounce scan


-p <port ranges>: Only scan specified ports

Ex: -p22; -p1-65535; -p U:53,111,137,T:21-25,80,139,8080,S:9

–exclude-ports <port ranges>: Exclude the specified ports from scanning

-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>


-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)


-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-args-file=filename: provide NSE script args in a file

–script-trace: Show all data sent and received

–script-updatedb: Update the script database.

–script-help=<Lua scripts>: Show help about scripts.

<Lua scripts> is a comma-separated list of script-files or



-O: Enable OS detection

–osscan-limit: Limit OS detection to promising targets

–osscan-guess: Guess OS more aggressively


Options which take <time> are in seconds, or append ‘ms’ (milliseconds),

‘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


-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

–proxies <url1,[url2],…>: Relay connections through HTTP/SOCKS4 proxies

–data <hex string>: Append a custom payload to sent packets

–data-string <string>: Append a custom ASCII string to sent packets

–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


-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)

–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


-6: Enable IPv6 scanning

-A: Enable OS detection, 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.


nmap -v -A scanme.nmap.org

nmap -v -sn

nmap -v -iR 10000 -Pn -p 80

SEE THE MAN PAGE (https://nmap.org/book/man.html) FOR MORE OPTIONS AND EXAMPLES