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Fast and full-featured SSL scanner


Current development of SSLyze now takes place on a separate repository:

This repository will periodically be updated from this new parent repository, but for the most current version, please check the new repo. If you cloned the repository but wish to track the new branch, you can update the origin using the following command:

git remote set-url origin


Fast and full-featured SSL scanner.


SSLyze is a Python tool that can analyze the SSL configuration of a server by connecting to it. It is designed to be fast and comprehensive, and should help organizations and testers identify misconfigurations affecting their SSL servers.

Key features include:

  • Multi-processed and multi-threaded scanning (it's fast)
  • SSL 2.0/3.0 and TLS 1.0/1.1/1.2 compatibility
  • Performance testing: session resumption and TLS tickets support
  • Security testing: weak cipher suites, insecure renegotiation, CRIME, Heartbleed and more
  • Server certificate validation and revocation checking through OCSP stapling
  • Support for StartTLS handshakes on SMTP, XMPP, LDAP, POP, IMAP, RDP and FTP
  • Support for client certificates when scanning servers that perform mutual authentication
  • XML output to further process the scan results
  • And much more !


SSLyze requires Python 2.7; the supported platforms are Windows 7 32/64 bits, Linux 32/64 bits and OS X 64 bits.

SSLyze is statically linked with OpenSSL. For this reason, the easiest way to run SSLyze is to download one the pre-compiled packages available in the GitHub releases section for this project, at


Command line options

The following command will provide the list of available command line options: $ python -h

Sample command line:

$ python --regular

See the test folder for additional examples.

Build / nassl

SSLyze is all Python code but since version 0.7, it uses a custom OpenSSL wrapper written in C called nassl. The pre-compiled packages for SSLyze contain a compiled version of this wrapper in sslyze/nassl. If you want to clone the SSLyze repo, you will have to get a compiled version of nassl from one of the SSLyze packages and copy it to sslyze-master/nassl, in order to get SSLyze to run.

The source code for nassl is hosted at

Py2exe Build

SSLyze can be packaged as a Windows executable by running the following command:

$ python.exe py2exe


GPLv2 - See LICENSE.txt.

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