RustScan Faster NMAP Scanner



  • Scans all 65k ports in 8 seconds (on 10k batch size).
  • Saves you time by automatically piping it into Nmap. No more manual copying and pasting!
  • Does one thing and does it well. Only purpose is to improve Nmap, not replace it!
  • Let’s you choose what Nmap commands to run, or uses the default.
  • IPv6 Support

bangbang Important Links

Installation GuideDocumentationDiscord
book Installation Guidebooks Documentationparrot Discord

raising_hand Table of Contents

telescope Why RustScan?

Why spend time running fast scans and manually copying the ports, or waiting for a 20 minute scan to finish when you can just do all 65k ports in less than a minute?


RustScan running in 8 seconds and finding all open ports out of 65k.

bar_chart RustScan vs Nmap vs MassScan

Actually usefulxwhite_check_markx
Realises it’s not useful, and pipes the only useful data into the only useful port scannerwhite_check_markxx

book Full Installation Guide

You need Nmap. If you have Kali Linux or Parrot OS installed, you already have Nmap. If not, follow the nmap install guide.

The easiest way to install RustScan is to use one of the packages provided for your system, such as HomeBrew or Yay for Arch Linux.

The most universal way is to use cargo, Rust’s built in package manager (think Pip but for Rust). Follow this guide to installing Rust & Cargo.

If you face any issues at all, please leave a GitHub issue. I have only tested this on Linux, so there may be issues for Mac OS or Windows.

Note: sometimes Rust doesn’t add Cargo to the path. Please see this issue for how to fix that.

desktop_computer Debian / Kali

Download the .deb file from the releases page:

Run the commpand dpkg -i on the file.

Note: sometimes you can double click the file to achieve the same result.

Docker whale

Docker is the recommended way of installing RustScan. This is because:

  • It has a high open file descriptor limit, which is one of the main problems with RustScan. Now you don’t have to fiddle around trying to understand your OS.
  • It works on all systems, regardless of OS. Even Windows, which we don’t officially support.
  • The Docker image uses the latest build from Cargo, our main source-of-truth package. This means that you will always be using the latest version.
  • No need to install Rust, Cargo, or Nmap.

To install Docker, follow their guide.

Once Docker is installed, you can either build your own image using the Dockerfile (alpine) provided in the repo, or alternatively, use the published Docker image like below (most convenient)

Please see our DockerHub for further info, however, note that we have two Docker images:



We strongly recommend using the alpine tag, as this is the latest major – stable – release of RustScan. This READMDE uses the alpine image by default, however, note that thelatest image is considered experimental.

To get started:

Simply run this command against the IP you want to target:

docker run -it --rm --name rustscan rustscan/rustscan:alpine <rustscan arguments here> <ip address to scan>

Note: this will scan the Docker’s localhost, not your own.

Once done, you will no longer need to re-download the image (except when RustScan updates) and can use RustScan like a normal application.

You will have to run this command every time, so we suggest aliasing it to something memorable.

alias rustscan='docker run -it --rm --name rustscan rustscan/rustscan:alpine <rustscan arguments here> <ip address to scan>'

Then we can:

rustscan -t 500 -b 1500 -- -A

To build your own image:

Download the repo:

git clone

Ensure you navigate to the download location of the repo:

cd /path/to/download/RustScan

Build away!

docker build -t <yourimagename> .

beer HomeBrew

Note for Mac users Mac OS has a very, very small ulimit size. This will negatively impact RustScan by a significant amount. Please use the Docker container, or tell RustScan to up the ulimit size on every run.

Tap the brew:

brew tap brandonskerritt/rustscan

Install it:

brew install rustscan

wrench Building it yourself

  1. Git clone the repo.
  2. Install Rust. You can do this with curl --proto '=https' --tlsv1.2 -sSf | sh which I took from the Rust website
  3. cd into the Git repo, and run cargo build --release
  4. The binary is located at target/release/rustscan
  5. Symlink to the binary or something. Whatever you want!

fox_face Community Distributions

Here are all of RustScan’s community distributions.

If you maintain a community distribution and want it listed here, leave an issue / pull request / Discord message or however you want to let us know.

Packaging status

cartwheeling Usage

rustscan -h
Fast Port Scanner built in Rust. WARNING Do not use this program against sensitive infrastructure since the specified
server may not be able to handle this many socket connections at once. - Discord - GitHub

    rustscan [FLAGS] [OPTIONS] <ips-or-hosts>... [-- <command>...]

    -a, --accessible
    -h, --help          Prints help information
    -q, --quiet         Quiet mode. Only output the ports. No Nmap. Useful for grep or outputting to a file
    -V, --version       Prints version information

    -b, --batch-size <batch-size>    The batch size for port scanning, it increases or slows the speed of scanning.
                                     Depends on the open file limit of your OS.  If you do 65535 it will do every port
                                     at the same time. Although, your OS may not support this [default: 4500]
    -p, --ports <ports>...           A list of comma separed ports to be scanned. Example: 80,443,8080.
    -r, --range <range>              A range of ports with format start-end. Example: 1-1000
        --scan-order <scan-order>    The order of scanning to be performed. The "serial" option will scan ports in
                                     ascending order while the "random" option will scan ports randomly [default:
                                     serial]  [possible values: Serial, Random]
    -t, --timeout <timeout>          The timeout in milliseconds before a port is assumed to be closed [default: 1500]
    -u, --ulimit <ulimit>            Automatically ups the ULIMIT with the value you provided

    <ips-or-hosts>...    A list of comma separated IP addresses or hosts to be scanned
    <command>...         The Nmap arguments to run. To use the argument -A, end RustScan's args with '-- -A'.
                         Example: 'rustscan -t 1500 -- -A -sC'. This command adds -Pn -vvv -p $PORTS
                         automatically to nmap. For things like --script '(safe and vuln)' enclose it in quotations
                         marks \"'(safe and vuln)'\"")

The format is rustscan -b 500 -T 1500 to scan with 500 batch size with a timeout of 1500ms. The timeout is how long RustScan waits for a response until it assumes the port is closed.

The batch size determines how fast RustScan is. Set it to 65k, and it will scan all 65k ports at the same time. This means at at 65k batch size, RustScan will take TIMEOUT long to scan all ports. Essentially, if timeout is 1000ms, RustScan can scan in 1 second.

Your operating system may not support this, but it is worth it to play around and see where your open file limit is. Shortly I will be releasing a dockerised version with a much larger open file limit, so this will be possible.

warning WARNING

This program, by default, scans 5000 ports at a time (5000 per second).

This may cause damage to a server, or may make it incredibly obvious you are scanning the server.

There are 2 ways to deal with this;

  1. Decrease batch size rustscan -b 10 will run 10 port scans for 1 second, and then another 10 for 1 second and so on.
  2. Increase timeout rustscan -T 5000 will mean RustScan waits 5 seconds until it scans the next ports.

You can also use both of these at the same time, to make it as slow or as fast as you want. A fun favourite is 65535 batch size with 1 second timeout. Theoretically, this scans all 65535 ports in 1 second.

Please do not use this tool against sensitive servers. It is designed mainly for Capture the Flag events, not real world servers with sensitive data.

rotating_light Thread Panicked at Main: Too Many Open Files

This is the most common error found in RustScan.

The open file limit is how many open sockets you can have at any given time.

This limit changes from OS to OS.

RustScan does not automatically create defaults (other than 5000) like Nmap does with their -T1, -T2 system.

By figuring out for yourself the optimal batch size, you will know that RustScan is the most optimised port scanner for your system.

There are 2 things you can do:

  1. Decrease batch size
  2. Increase open file limit

Decreasing batch size slows down the program, so as long as it isn’t too drastic, this is a good option.

Run these 3 commands:

ulimit -a
ulimit -Hn
ulimit -Sn

They will give you an idea on the open file limit of your OS.

If it says “250”, run rustscan -b 240 for a batch size of 240.

Increasing the open file limit increases speed, but poses danger. Although, opening more file sockets on the specified IP address may damage it.

To open more, set the ulimit to a higher number:

ulimit -n 5000

Mac OS Mac OS has, from what I can tell, a naturally very low open file descriptor limit. The limit for Ubuntu is 8800. The limit for Mac OS is 255!

In this case, I would say it is safe to increase the open file limit. As most Linux based OS’ have limits in the thousands.

Although, if this breaks anything, please don’t blame me.

Windows Subsystem for Linux Windows Subsystem for Linux does not support ulimit (see issue #39).

The best way is to use it on a host computer, in Docker, or in a VM that isn’t WSL.

Automatic Ulimit updating We are currently working on automatic Ulimit updating. If it is too high, it will lower itself. If it is too low, it will suggest a higher Ulimit. Watch this issue for more.

electric_plug Nmap Custom Flags

To run your own nmap commands, end the RustScan command with -- -A where -- indicates “end of RustScan flags, please do not parse anything further” and any flags after that will be entered into nmap.

RustScan automatically runs nmap -vvv -p $PORTS $IP. To make it run -A, execute the command rustscan -- -A.

If you want to run commands such as --script (vuln and safe), you will need to enclose it in quotations like so --script '"(vuln and safe) or default"'.

dart Increasing speed / accuracy

  • Batch size

This increases speed, by allowing us to process more at once. Something experimental I am working on is changing the open file limit. You can do this manually with ulimit -n 70000 and then running rustscan with -b 65535. This should scan all 65535 ports at the exact same time. But this is extremely experimental.

For non-experimental speed increases, slowly increase the batch size until it no longer gets open ports, or it breaks.

  • Accuracy (and some speed)

To increase accuracy, the easiest way is to increase the timeout. The default is 1.5 seconds, by setting it to 4 seconds (4000) we are telling RustScan “if we do not hear back from a port in 4 seconds, assume it is closed”.

Decreasing accuracy gives some speed bonus, but my testing found that batch size dramatically changed the speed whereas timeout did, but not so much.

circus_tent Community

Howdy Space Cow-Person cowboy_hat_facemilky_way

RustScan is always looking for contributors. Whether that’s spelling mistakes or major changes, your help is wanted and welcomed here.

Before contributing, read our code of conduct.

TL;DR if you abuse members of our community you will be perma-banned hugs

RustScan has 2 major labels for GitHub issues you should look at:

If you want to, solve the issue or comment on the issue for help.

The flow for contributing to open source software is:

  • Fork the repo
  • Make changes
  • Pull request to the repo

And then comment on the issue that you’ve done.

RustScan also has some // TODO‘s in the codebase, which are meant more for the core team but we wouldn’t say no to help with these issues.

If you have any feature suggestions or bugs, leave a GitHub issue. We welcome any and all support 😀

We communicate over Discord. Click here to join our Discord community!

Rewarding you

I cannot pay you 🙁 But, I can place your GitHub profile on the README under #Contributors as a thank you! 🙂

Please read the file


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