Isabelle is a popular generic theorem prover developed at Cambridge University and TU Munich. Existing logics like Isabelle/HOL provide a theorem proving environment ready to use for sizable applications. Isabelle may also serve as framework for rapid prototyping of deductive systems. It comes with a large library including Isabelle/HOL (classical higher-order logic), Isabelle/HOLCF (Scott's Logic for Computable Functions with HOL), Isabelle/FOL (classical and intuitionistic first-order logic), and Isabelle/ZF (Zermelo-Fraenkel set theory on top of FOL).
The OpenCA Project is a collaborative effort to develop a robust, full-featured and Open Source out-of-the-box Certification Authority implementing the most used protocols with full-strength cryptography world-wide. OpenCA is based on many Open-Source Projects. Among the supported software is OpenLDAP, OpenSSL, Apache Project, Apache mod_ssl.
passwdqc is a password/passphrase strength checking and policy enforcement tool set, including an optional PAM module (pam_passwdqc), command-line programs (pwqcheck and pwqgen), and a library (libpasswdqc). On systems with PAM, pam_passwdqc is normally invoked on password changes by programs such as passwd(1). It is capable of checking password or passphrase strength, enforcing a policy, and offering randomly-generated passphrases, with all of these features being optional and easily (re-)configurable. pwqcheck and pwqgen are standalone password/passphrase strength checking and random passphrase generator programs, respectively, and are usable from scripts. libpasswdqc is the underlying library, which may also be used from third-party programs.
ZMailer is an internet message transfer agent. It is intended for gateways or mail servers or other large site environments that have extreme demands on the abilities of the mailer. It was motivated by the problems of the Sendmail design in such situations. It is intended and designed as a multi-protocol mailer. The only protocol supported in this distribution is RFC822 (and variations).
Onyx is a powerful stack-based, multi-threaded, interpreted, general purpose programming language similar to PostScript and Forth. It can be embedded as an extension language into other applications, and was designed to have a small memory footprint. It is among the smallest embeddable interpreters available.
nefu (network fidelity utility) is a Unix daemon that monitors services over the network. It uses a "no false alarms" fault verification algorithm, and understands network dependancies. Natively-monitored protocols include ICMP echo (ping), SSH, IPP, DNS, HTTP, POP, NTP, IMAP, SMTP, and LDAP, as well as having facilities to execute external programs. Status pages are available via finger or the Web.