↓ download on github


testssl.sh 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
  • Ease of installation: It works for Linux, Darwin, FreeBSD, NetBSD and MSYS2/Cygwin out of the box: no need to install or configure something, no gems, CPAN, pip or the like.
  • Flexibility: You can test any SSL/TLS enabled and STARTTLS service, not only webservers at port 443
  • Toolbox: Several command line options help you to run YOUR test and configure YOUR output
  • Reliability: features are tested thoroughly
  • Verbosity: If a particular check cannot be performed because of a missing capability on your client side, you’ll get a warning
  • 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 and you can change it.
  • Heck, even the development is open (github)


Here in the 2.9dev branch you find the development version of the software -- with new features and maybe some bugs. For the stable version and a more thorough description of the command line options please see [testssl.sh](https://testssl.sh/ "Go to the site with the stable version and more documentation") or https://github.com/drwetter/testssl.sh/wiki/Usage-Documentation.


testssl.sh is working on every Linux/BSD distribution out of the box. In 2.9dev most of the limitations of disabled features from the openssl client are gone due to bash-socket-based checks. testssl.sh also works on otherunixoid system out of the box, supposed they have /bin/bash and standard tools like sed and awk installed. System V needs to have GNU versions of grep and sed installed. MacOS X and Windows (using MSYS2 or cygwin) work too. OpenSSL version >= 1 is a must. OpenSSL version >= 1.0.2 is needed for better LOGJAM checks and to display bit strengths for key exchanges.

Update notification here or @ https://twitter.com/drwetter.

Features implemented in Readme.md#devel

  • Support of supplying timeout value for openssl connect — useful for batch/mass scanning
  • TLS 1.2 protocol check via socket
  • Further tests via TLS sockets and improvements (handshake parsing, completeness, robustness)
  • Finding more TLS extensions via sockets
  • Using bash sockets where ever possible
  • TLS Supported Groups Registry (RFC 7919), key shares extension
  • Non-flat JSON support
  • File output (CSV, JSON flat, JSON non-flat) supports a minimum severity level (only above supplied level there will be output)
  • Native HTML support instead going through ’aha’
  • Testing 359 default ciphers (testssl.sh -e) with a mixture of sockets and openssl. Same speed as with openssl only but addtional ciphers such as post-quantum ciphers, new CHAHA20/POLY1305, CamelliaGCM etc.
  • LUCKY13 and SWEET32 checks
  • LOGJAM: now checking also for known DH parameters
  • Check for CAA RR
  • Check for OCSP must staple
  • Better formatting of output (indentation)
  • Choice showing the RFC naming scheme only

Features planned in 2.9dev



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

There’s a https://github.com/drwetter/testssl.sh/wiki/Coding-Style.

Please file bug reports @ https://github.com/drwetter/testssl.sh/issues.


For a start see the wiki. Help is needed here.

Bug reports

Please file bugs in the issue tracker. Do not forget to provide detailed information, see https://github.com/drwetter/testssl.sh/wiki/Bug-reporting. (Nobody can read your thoughts — yet. And only agencies your screen) ;-)

External/related projects

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

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Ready-to-go docker images are available at:

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