Workstation

The Yubico Pluggable Authentication Module (PAM) provides an easy way to integrate the YubiKey into existing user authentication infrastructures. PAM is used by GNU/Linux, Solaris and Mac OS X for user authentication. There is an offline validation option via the use of HMAC-SHA1 Challenge-Response feature of the YubiKey. The PAM module supports YubiKey coupled with FreeRadius, OpenVPN, Radius, SELinux on Fedora 18 and up, or SSH.

Server

The Yubico PAM provides an easy way to integrate the YubiKey into existing user authentication infrastructures. PAM is used by GNU/Linux, Solaris and Mac OS X for user authentication.

U2F

The PAM U2F module provides an easy way to integrate the Yubikey into your existing user authentication infrastructure. The module supports PAM authentication using U2F.

Red Hat

Red Hat Enterprise Linux (RHEL) 7.1 contains Red Hat’s first implementation of the standard OTPs leveraging the open standard OATH HOTP and TOTP, which are both supported by the YubiKey. This functionality is part of the Identity Management features in RHEL 7.1.