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About the developer

5.2K Stars 711 Forks GNU General Public License v2.0 3.8K Commits 204 Opened issues


Testing TLS/SSL encryption anywhere on any port

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Travis CI Status Gitter License Docker
is a free command line tool which checks a server's service on any port for the support of TLS/SSL ciphers, protocols as well as some cryptographic flaws.

Key features

  • Clear output: you can tell easily whether anything is good or bad.
  • Machine readable output (CSV, two JSON formats)
  • No need to install or to configure something. No gems, CPAN, pip or the like.
  • Works out of the box: Linux, OSX/Darwin, FreeBSD, NetBSD, MSYS2/Cygwin, WSL (bash on Windows). Only OpenBSD needs bash.
  • A Dockerfile is provided, there's also an offical container build @ dockerhub.
  • Flexibility: You can test any SSL/TLS enabled and STARTTLS service, not only web servers at port 443.
  • Toolbox: Several command line options help you to run your test and configure your output.
  • Reliability: features are tested thoroughly.
  • Privacy: It's only you who sees the result, not a third party.
  • Freedom: It's 100% open source. You can look at the code, see what's going on.
  • The development is open (github) and participation is welcome.


This software is free. You can use it under the terms of GPLv2, see LICENSE.

Attribution is important for the future of this project -- also in the internet. Thus if you're offering a scanner based on as a public and/or paid service in the internet you are strongly encouraged to mention to your audience that you're using this program and where to get this program from. That helps us to get bugfixes, other feedback and more contributions.

Compatibility is working on every Linux/BSD distribution out of the box. Latest by 2.9dev most of the limitations of disabled features from the openssl client are gone due to bash-socket-based checks. As a result you can also use e.g. LibreSSL or OpenSSL >= 1.1.1 . also works on other unixoid systems out of the box, supposed they have

>= version 3.2 and standard tools like sed and awk installed. An implicit (silent) check for binaries is done when you start . System V needs probably to have GNU grep installed. MacOS X and Windows (using MSYS2, Cygwin or WSL) work too.

Update notification here or @ twitter.


You can download branch 3.1dev just by cloning this git repository:

git clone --depth 1

Think of 3.1dev like a rolling release, see below. For the stable version help yourself by downloading the ZIP or tar.gz archive. Just

to the directory created (=INSTALLDIR) and run it off there.

Docker has minimal requirements. As stated you don't have to install or build anything. You can just run it from the pulled/cloned directory. Still if you don't want to pull the github repo to your directory of choice you can pull a container from dockerhub and run it:

docker run --rm -ti  drwetter/ 

Or if you have cloned this repo you also can just

to the INSTALLDIR and run
docker build . -t imagefoo && docker run --rm -t imagefoo

For more please consult


We're currently in the development phase, version 3.1dev. 3.1dev will eventually become 3.2. Bigger features are developed in a separate branch before merged into 3.1dev to avoid hiccups or inconsistencies. Albeit we try to keep 3.1dev as solid as possible things will certainly change in 3.1dev. Think of the 3.1dev branch like a rolling release. So if you need stability the 3.0 branch is better for you.

Version 3.0.X receives bugfixes, labeled as 3.0.1, 3.0.2 and so on. This will happen until 3.2 is released.

Support for 2.9.5 has been dropped. Supported is >= 3.0.x only.


  • .. it is there for reading. Please do so :-) -- at least before asking questions. See man page in groff, html and markdown format in
  • will help to get you started.
  • For the (older) version 2.8 will Hunt provides a longer, good description, including useful background info.


Contributions are welcome! See for details. Please also have a look at the Coding Convention.

Bug reports

Bug reports are important. It makes this project more robust.

Please file bugs in the issue tracker @ github. Do not forget to provide detailed information, see template for issue, and further details @ Nobody can read your thoughts -- yet. And only agencies your screen ;-)

You can also debug yourself, see here.

External/related projects

Please address questions not specifically to the code of to the respective projects below.

Web frontend


Free to use Web frontend + commercial API

  • (see also

Mass scanner w parallel scans and elastic searching the results


Another ready-to-go docker image is at:


Privacy checker using


Nagios / Icinga Plugins

  • (Python 3)
  • (Shell)

Brew package

Daemon for batch execution of command files


Daemon for batch processing of JSON result files for sending Slack alerts, reactive copying etc


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