The old libntlm (note lower case) was a library that implement Microsoft's NTLM authentication. However, the packaging of libntlm lacked certain things, such as having build problems, lacking shared library support, lacking autoconf macro for use in other applications, lacking pkg-config support, and more. So this page distributes an improved version of the library; called Libntlm (note upper case L to differentiate it from the original libntlm). Compared to the original releases, the current version has been entirely re-written and only shares the same function interfaces.

Libntlm is licensed under the GNU Lesser General Public License version 2.1 or (at your option) any later version.

References for the NTLM protocol are:

Projects using Libntlm include GNU SASL.

What's new


The releases are distributed from release directory.

All releases are signed with an OpenPGP key with fingerprint 0xB565716F.

Free support

A mailing list where Libntlm users may help each other exists, and you can reach it by sending e-mail to Archives of the mailing list discussions, and an interface to manage subscriptions, is available through the World Wide Web at

There is also the Libntlm project page at Savannah that provide a bug tracker and more.

Paid support

If you are interested in paid support of Libntlm please contact me.

This work is sponsored by Simon Josefsson Datakonsult AB. If you find my work in this area useful, also please consider making a donation. No amount is too small!


There is a Savannah Libntlm project page. You can check out the sources by using git as follows:

$ git clone git://

The online git interface is available.

If you have trouble using git, you may download a daily snapshot. The snapshots are prepared similar to regular releases, i.e., you simply build them using ./configure && make.

Build logs from building the package, where you can also contribute a build system for your own platform, are available from the Libntlm autobuild page.

Simon Josefsson