The one downside to a tool as robust and powerful as Nmap is remembering so many commands. Even many seasoned industry professionals fail to make the most of Nmap simply because keeping track of all its flags can prove such a challenge.
We have compiled and organized this Nmap cheat sheet to help you master what is arguably the most useful tool in any penetration tester’s arsenal. Whether you use it to memorize Nmap’s options, as a quick reference to keep nearby, or as a study sheet for your CEH/Pentest+ exam, we’re certain it will help you become a Nmap pro.
Download your own copy of this cheat sheet here. Now, let’s get to the Nmap commands.
Nmap Cheat Sheet Search
Search our Nmap cheat sheet to find the right cheat for the term you're looking for. Simply enter the term in the search bar and you'll receive the matching cheats available.
Table Of Contents
- Nmap Cheat Sheet Search
- Target Specification
- Nmap Scan Techniques
- Host Discovery
- Nmap Command Generator
- Port Specification
- Service and Version Detection
- OS Detection
- Timing and Performance
- Timing and Performance Switches
- NSE Scripts
- Useful NSE Script Examples
- Firewall / IDS Evasion and Spoofing
- Output
- Helpful Nmap Output examples
- Miscellaneous Nmap Flags
- Other Useful Nmap Commands
- Frequently Asked Questions
Target Specification
| SWITCH | EXAMPLE | DESCRIPTION |
|---|---|---|
| nmap 192.168.1.1 | Scan a single IP | |
| nmap 192.168.1.1 192.168.2.1 | Scan specific IPs | |
| nmap 192.168.1.1-254 | Scan a range | |
| nmap scanme.nmap.org | Scan a domain | |
| nmap 192.168.1.0/24 | Scan using CIDR notation | |
| -iL | nmap -iL targets.txt | Scan targets from a file |
| -iR | nmap -iR 100 | Scan 100 random hosts |
| -exclude | nmap -exclude 192.168.1.1 | Exclude listed hosts |
Nmap Scan Techniques
| SWITCH | EXAMPLE | DESCRIPTION |
|---|---|---|
| -sS | nmap 192.168.1.1 -sS | TCP SYN port scan (Default) |
| -sT | nmap 192.168.1.1 -sT | TCP connect port scan (Default without root privilege) |
| -sU | nmap 192.168.1.1 -sU | UDP port scan |
| -sA | nmap 192.168.1.1 -sA | TCP ACK port scan |
| -sW | nmap 192.168.1.1 -sW | TCP Window port scan |
| -sM | nmap 192.168.1.1 -sM | TCP Maimon port scan |
Host Discovery
| SWITCH | EXAMPLE | DESCRIPTION |
|---|---|---|
| -sL | nmap 192.168.1.1-3 -sL | No Scan. List targets only |
| -sn | nmap 192.168.1.1/24 -sn | Disable port scanning. Host discovery only. |
| -Pn | nmap 192.168.1.1-5 -Pn | Disable host discovery. Port scan only. |
| -PS | nmap 192.168.1.1-5 -PS22-25,80 | TCP SYN discovery on port x. Port 80 by default |
| -PA | nmap 192.168.1.1-5 -PA22-25,80 | TCP ACK discovery on port x. Port 80 by default |
| -PU | nmap 192.168.1.1-5 -PU53 | UDP discovery on port x. Port 40125 by default |
| -PR | nmap 192.168.1.1-1/24 -PR | ARP discovery on local network |
| -n | nmap 192.168.1.1 -n | Never do DNS resolution |
Nmap Command Generator
Say goodbye to the hassle of trying to remember the exact syntax for your Nmap commands! With our Nmap Command Generator, you can simply say what you need Nmap to do and we will generate the command for you.
Port Specification
| SWITCH | EXAMPLE | DESCRIPTION |
|---|---|---|
| -p | nmap 192.168.1.1 -p 21 | Port scan for port x |
| -p | nmap 192.168.1.1 -p 21-100 | Port range |
| -p | nmap 192.168.1.1 -p U:53,T:21-25,80 | Port scan multiple TCP and UDP ports |
| -p | nmap 192.168.1.1 -p- | Port scan all ports |
| -p | nmap 192.168.1.1 -p http,https | Port scan from service name |
| -F | nmap 192.168.1.1 -F | Fast port scan (100 ports) |
| -top-ports | nmap 192.168.1.1 -top-ports 2000 | Port scan the top x ports |
| -p-65535 | nmap 192.168.1.1 -p-65535 | Leaving off initial port in range makes the scan start at port 1 |
| -p0- | nmap 192.168.1.1 -p0- | Leaving off end port in range makes the scan go through to port 65535 |
Service and Version Detection
| SWITCH | EXAMPLE | DESCRIPTION |
|---|---|---|
| -sV | nmap 192.168.1.1 -sV | Attempts to determine the version of the service running on port |
| -sV -version-intensity | nmap 192.168.1.1 -sV -version-intensity 8 | Intensity level 0 to 9. Higher number increases possibility of correctness |
| -sV -version-light | nmap 192.168.1.1 -sV -version-light | Enable light mode. Lower possibility of correctness. Faster |
| -sV -version-all | nmap 192.168.1.1 -sV -version-all | Enable intensity level 9. Higher possibility of correctness. Slower |
| -A | nmap 192.168.1.1 -A | Enables OS detection, version detection, script scanning, and traceroute |
OS Detection
| SWITCH | EXAMPLE | DESCRIPTION |
|---|---|---|
| -O | nmap 192.168.1.1 -O | Remote OS detection using TCP/IP stack fingerprinting |
| -O -osscan-limit | nmap 192.168.1.1 -O -osscan-limit | If at least one open and one closed TCP port are not found it will not try OS detection against host |
| -O -osscan-guess | nmap 192.168.1.1 -O -osscan-guess | Makes Nmap guess more aggressively |
| -O -max-os-tries | nmap 192.168.1.1 -O -max-os-tries 1 | Set the maximum number x of OS detection tries against a target |
| -A | nmap 192.168.1.1 -A | Enables OS detection, version detection, script scanning, and traceroute |
Timing and Performance
| SWITCH | EXAMPLE | DESCRIPTION |
|---|---|---|
| -T0 | nmap 192.168.1.1 -T0 | Paranoid (0) Intrusion Detection System evasion |
| -T1 | nmap 192.168.1.1 -T1 | Sneaky (1) Intrusion Detection System evasion |
| -T2 | nmap 192.168.1.1 -T2 | Polite (2) slows down the scan to use less bandwidth and use less target machine resources |
| -T3 | nmap 192.168.1.1 -T3 | Normal (3) which is default speed |
| -T4 | nmap 192.168.1.1 -T4 | Aggressive (4) speeds scans; assumes you are on a reasonably fast and reliable network |
| -T5 | nmap 192.168.1.1 -T5 | Insane (5) speeds scan; assumes you are on an extraordinarily fast network |
Timing and Performance Switches
| SWITCH | EXAMPLE INPUT | DESCRIPTION |
|---|---|---|
| -host-timeout<time> | 1s; 4m; 2h | Give up on target after this long |
| -min-rtt-timeout/max-rtt-timeout/initial-rtt-timeout<time> | 1s; 4m; 2h | Specifies probe round trip time |
| -min-hostgroup/max-hostgroup<size<size> | 50; 1024 | Parallel host scan group sizes |
| -min-parallelism/max-parallelism<numprobes> | 10; 1 | Probe parallelization |
| -max-retries <tries> | 3 | Specify the maximum number of port scan probe retransmissions |
| -min-rate<number> | 100 | Send packets no slower than<number> per second |
| -max-rate <number> | 100 | Send packets no faster than<number> per second |
NSE Scripts
| SWITCH | EXAMPLE | DESCRIPTION |
|---|---|---|
| -sC | nmap 192.168.1.1 -sC | Scan with default NSE scripts. Considered useful for discovery and safe |
| -script default | nmap 192.168.1.1 -script default | Scan with default NSE scripts. Considered useful for discovery and safe |
| -script | nmap 192.168.1.1 -script=banner | Scan with a single script. Example banner |
| -script | nmap 192.168.1.1 -script=http* | Scan with a wildcard. Example http |
| -script | nmap 192.168.1.1 -script=http,banner | Scan with two scripts. Example http and banner |
| -script | nmap 192.168.1.1 -script "not intrusive" | Scan default, but remove intrusive scripts |
| -script-args | nmap -script snmp-sysdescr -script-args snmpcommunity=admin 192.168.1.1 | NSE script with arguments |
Useful NSE Script Examples
| COMMAND | DESCRIPTION |
|---|---|
| nmap -Pn -script=http-sitemap-generator scanme.nmap.org | http site map generator |
| nmap -n -Pn -p 80 -open -sV -vvv -script banner,http-title -iR 1000 | Fast search for random web servers |
| nmap -Pn -script=dns-brute domain.com | Brute forces DNS hostnames guessing subdomains |
| nmap -n -Pn -vv -O -sV -script smb-enum*,smb-ls,smb-mbenum,smb-os-discovery,smb-s*,smb-vuln*,smbv2* -vv 192.168.1.1 | Safe SMB scripts to run |
| nmap -script whois* domain.com | Whois query |
| nmap -p80 -script http-unsafe-output-escaping scanme.nmap.org | Detect cross site scripting vulnerabilities |
| nmap -p80 -script http-sql-injection scanme.nmap.org | Check for SQL injections |
Firewall / IDS Evasion and Spoofing
| SWITCH | EXAMPLE | DESCRIPTION |
|---|---|---|
| -f | nmap 192.168.1.1 -f | Requested scan (including ping scans) use tiny fragmented IP packets. Harder for packet filters |
| -mtu | nmap 192.168.1.1 -mtu 32 | Set your own offset size |
| -D | nmap -D 192.168.1.101,192.168.1.102,192.168.1.103,192.168.1.23 192.168.1.1 | Send scans from spoofed IPs |
| -D | nmap -D decoy-ip1,decoy-ip2,your-own-ip,decoy-ip3,decoy-ip4 remote-host-ip | Above example explained |
| -S | nmap -S www.microsoft.com www.facebook.com | Scan Facebook from Microsoft (-e eth0 -Pn may be required) |
| -g | nmap -g 53 192.168.1.1 | Use given source port number |
| -proxies | nmap -proxies http://192.168.1.1:8080, http://192.168.1.2:8080 192.168.1.1 | Relay connections through HTTP/SOCKS4 proxies |
| -data-length | nmap -data-length 200 192.168.1.1 | Appends random data to sent packets |
Example IDS Evasion command
nmap -f -t 0 -n -Pn --data-length 200 -D
192.168.1.101,192.168.1.102,192.168.1.103,192.168.1.23 192.168.1.1
Output
| SWITCH | EXAMPLE | DESCRIPTION |
|---|---|---|
| -oN | nmap 192.168.1.1 -oN normal.file | Normal output to the file normal.file |
| -oX | nmap 192.168.1.1 -oX xml.file | XML output to the file xml.file |
| -oG | nmap 192.168.1.1 -oG grep.file | Grepable output to the file grep.file |
| -oA | nmap 192.168.1.1 -oA results | Output in the three major formats at once |
| -oG - | nmap 192.168.1.1 -oG - | Grepable output to screen. -oN -, -oX - also usable |
| -append-output | nmap 192.168.1.1 -oN file.file -append-output | Append a scan to a previous scan file |
| -v | nmap 192.168.1.1 -v | Increase the verbosity level (use -vv or more for greater effect) |
| -d | nmap 192.168.1.1 -d | Increase debugging level (use -dd or more for greater effect) |
| -reason | nmap 192.168.1.1 -reason | Display the reason a port is in a particular state, same output as -vv |
| -open | nmap 192.168.1.1 -open | Only show open (or possibly open) ports |
| -packet-trace | nmap 192.168.1.1 -T4 -packet-trace | Show all packets sent and received |
| -iflist | nmap -iflist | Shows the host interfaces and routes |
| -resume | nmap -resume results.file | Resume a scan |
Helpful Nmap Output examples
| COMMAND | DESCRIPTION |
|---|---|
| nmap -p80 -sV -oG - -open 192.168.1.1/24 | grep open | Scan for web servers and grep to show which IPs are running web servers |
| nmap -iR 10 -n -oX out.xml | grep "Nmap" | cut -d " " -f5 > live-hosts.txt | Generate a list of the IPs of live hosts |
| nmap -iR 10 -n -oX out2.xml | grep "Nmap" | cut -d " " -f5 >> live-hosts.txt | Append IP to the list of live hosts |
| ndiff scanl.xml scan2.xml | Compare output from nmap using the ndif |
| xsltproc nmap.xml -o nmap.html | Convert nmap xml files to html files |
| grep " open " results.nmap | sed -r ‘s/ +/ /g’ | sort | uniq -c | sort -rn | less | Reverse sorted list of how often ports turn up |
Miscellaneous Nmap Flags
| SWITCH | EXAMPLE | DESCRIPTION |
|---|---|---|
| -6 | nmap -6 2607:f0d0:1002:51::4 | Enable IPv6 scanning |
| -h | nmap -h | nmap help screen |
Other Useful Nmap Commands
| COMMAND | DESCRIPTION |
|---|---|
| nmap -iR 10 -PS22-25,80,113,1050,35000 -v -sn | Discovery only on ports x, no port scan |
| nmap 192.168.1.1-1/24 -PR -sn -vv | Arp discovery only on local network, no port scan |
| nmap -iR 10 -sn -traceroute | Traceroute to random targets, no port scan |
| nmap 192.168.1.1-50 -sL -dns-server 192.168.1.1 | Query the Internal DNS for hosts, list targets only |
| nmap 192.168.1.1 --packet-trace | Show the details of the packets that are sent and received during a scan and capture the traffic. |
You are only doing yourself a disservice by failing to learn and utilize all of Nmap’s features. It is the first go-to tool you will use in the scanning and enumeration stage of many assessments, setting the foundation for the rest of your pentest.
Keep a copy of this Nmap cheat sheet to refer back to, and consider our Complete Nmap Ethical Hacking Course. It, and many other ethical hacking courses, are available in our VIP Member’s Section.
Frequently Asked Questions
What is Nmap, and why is it used?
Nmap is a free network scanning tool used to discover hosts and services on a network by analyzing responses to various packets and requests.
What is the Nmap command used for?
Penetration testers and network administrators will use Nmap to discover machines on a network and their open ports, running services, operating systems, and a wealth of other useful information.
Is Nmap scanning legal?
This depends on your jurisdiction. In many places, the answer is no, not without prior permission from the owner of the site or network.
We recommend reading a more complete answer in our article, Is Port Scanning Legal?
What can we hack with Nmap?
Nmap is a tool used for scanning and enumeration. Hackers and penetration testers use the information gathered to see what the available attack surface is.
However, there are a great number of NSE scripts that can perform such actions as password brute forcing, checking for backup and configuration files, searching for remote file inclusion (RFI) vulnerabilities, and testing default credentials.
How do I scan an IP with Nmap?
A basic scan of a single IP address is as easy as:
nmap <ip>
This will return if the host is up and responding to ping, what ports are open, and what services are running on them. More complex commands can be found in the cheat sheet above.
Is it OK to Nmap Google?
The long answer is, it depends on your jurisdiction. The short answer is, probably not and you shouldn’t do it. Even if it isn’t illegal where you live, it will most certainly violate Google’s terms of service.
Do firewalls block Nmap?
Firewalls can block access to ports, which would indeed block Nmap. Nmap does have flags to attempt to evade firewalls and intrusion detection systems, which we have listed in the cheat sheet above.
Is Nmap a vulnerability?
After you have installed Nmap on your host system, an over-ambitious antivirus program may flag it as malicious. So long as you have downloaded it from the official Nmap website, it is safe to have installed.
Can Nmap bypass a firewall?
Nmap has several optional services which can attempt to bypass firewalls and spoof its scans. See the Firewall / IDS Evasion and Spoofing section above for details.
Can Nmap hack WiFi?
Nmap has many NSE scripts designed to brute force different services and logins. Depending on the login portal, there may be a relevant script to do so.
More realistically, Nmap would be used to enumerate the network, and one of many free programs better suited to WiFi hacking would be used afterward.
Can Nmap crack passwords?
Nmap has many brute force scripts which will automate password login attempts on various services, such as MySQL, Telenet, and POP3. This may provide a quick win, but password attacks are better handled by tools dedicated to that purpose, such as THC Hydra.
How do I read Nmap results?
Fortunately, even the more complex Nmap scans display their results in a clear and easy-to-follow manner. You also have the ability to output the data in various forms, including as an XML or grepable file (see the Output section for details).
You can also see our Zenmap vs. Nmap article to learn about the graphical version of the tool.
Level Up in Cyber Security: Join Our Membership Today!
MEMBERSHIP
Nathan House Nathan House is the founder and CEO of StationX. He has over 25 years of experience in cyber security, where he has advised some of the largest companies in the world. Nathan is the author of the popular "The Complete Cyber Security Course", which has been taken by over half a million students in 195 countries. He is the winner of the AI "Cyber Security Educator of the Year 2020" award and finalist for Influencer of the year 2022.
