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Dirk Wetter 3d5982e60b
Merge pull request #1285 from dcooper16/fix_color_comparison_typo
1 day ago
.github fix numbering 2 months ago
bin name is openssl.Linux.x86_64.krb now 3 months ago
doc Formatting fixed 1 month ago
etc Deprecation of more clients 1 month ago
t In line with the new scheme now 1 month ago
utils Don't include SSLv2 ciphers in 1 month ago
.gitignore update 2 years ago
.travis.yml Fix travis 2 months ago Add SNI/STARTTLS, pwnedkeys 1 week ago Test for vulnerability to Bleichenbacher attack 1 year ago
Dockerfile Use specific Alpine version 2 months ago Update 2 months ago
LICENSE Initial commit 5 years ago Polish readme and reflect branch change to 3.0 2 months ago
openssl-iana.mapping.html RFC --> IANA 7 months ago Fix typo in check of $COLOR 1 day ago


Build Status Gitter 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.
  • No installation needed: Linux, OSX/Darwin, FreeBSD, NetBSD, MSYS2/Cygwin, WSL work out of the box. Only OpenBSD needs bash. No need to install or to configure something. No gems, CPAN, pip or the like.
  • A Dockerfile is provided, there’s also an offical container @ 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. In addition starting from version 3.0rc1 if you’re offering a scanner based on as a public and / or paid service in the internet you need to mention to your audience that you’re using this program and where to get this program from.

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 system out of the box, supposed they have /bin/bash >= 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 by cloning this git repository:

git clone --depth 1

Or help yourself downloading the ZIP archive --help will give you some help upfront. More help: see doc directory with man pages. Older sample runs are at

Running a docker container from dockerhub

 docker run -ti drwetter/ <your_cmd_line>


We’re currently in the late release candidate phase. That means you can and should use it for production and let us know if you encounter any additional bugs. Features implemented in 3.0 are listed in the Changelog.

Support for 2.9.5 has been dropped.


  • It is for reading. Please do so :-) at least before asking questions.
  • There’s a man page in groff, html and markdown format in ~/doc/.
  • will help to get you started.
  • Will Hunt provides a longer, good description for the version 2.8, including useful background info.


Contributions, feedback, bug reports are welcome! For contributions please note: One patch per feature -- bug fix/improvement. Please test your changes thoroughly as reliability is important for this project.

There’s a coding guideline.

Bug reports

Please file bugs in the issue tracker @ github. Do not forget to provide detailed information, see template. 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.

Cool web frontend

Mass scanner w parallel scans and elastic searching the results

Another ready-to-go docker image is at:

Privacy checker using

Brew package

Daemon for batch execution of command files

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