NASLite is a Network Attached Storage (NAS) server operating system designed to transform a basic computer into a dedicated file server. Utilizing highly optimized versions of Samba, uCLibc, BusyBox, and various other Linux tools, it provides SMB/CIFS, FTP, or NFS filesystem support. It accommodates multiple client OSes: Windows, Mac OS X, and Linux. NASLite offers SMART disk monitoring and large file support, and is incredibly easy to install and administer.
TrinityOS is a step-by-step, example-driven HOWTO on building a very functional Linux box with strong security in mind. TrinityOS is well known for its strong packet firewall ruleset, Chrooted and Split DNS (v9 and v8), secured Sendmail (8.x), Linux PPTP, Serial consoles and Reverse TELNET, DHCPd, SSHd, UPSes, system performance tuning, the automated TrinityOS-Security implementation scripts, and much more.
conexus is a generalized C++ I/O library that includes network support for IPv4 and IPv6 sockets, serial/TTY communications, kernel message queues, pipes, and files. Objects use sigc++ for signaling property changes and other information. Sub-libraries include conexus-gtkmm (provides a set of gtkmm widgets), conexus-dbus (provides dbus support for endpoints), conexus-nspr (provides NSPR endpoints), conexus-nss (provides NSS endpoints), and conexus-ssl (provides OpenSSL endpoints).
ThePacketMaster Linux Security Server is a CD-based security auditing tool that boots and runs penetration testing and forensic analysis tools. It is handy for security auditors. Some tools included are nessus, ethereal, The Coroner's Toolkit, chntpw, and minicom. It includes modules for any Linux 2.4.20 SCSI driver.
Exscript is a scripting language for automating network connections over protocols such as Telnet or SSH. It is in some ways comparable to Expect, but has some unique features that make it a lot easier to use and understand for non-developers. It supports parallelization, logging, authentication mechanisms, and a lot more.
rrs is a reverse (connecting) remote shell. Instead of listening, it will connect out to rrs in listen mode. The listener will accept the connection and receive a shell from the remote host. rrs features full pseudo-TTY support, full OpenSSL support (client/server authentication and choice of cipher suites), Twofish encryption, a simple XOR cipher, plain-text sessions, peer-side session snooping, a daemon option, and reconnection features. It is known to compile and run under Linux, FreeBSD, NetBSD, OpenBSD, and QNX.
DIET-PC (DIskless Embedded Technology Personal Computer) is a software kit enabling IT professionals to build embedded Linux appliances based on commodity PC or Mac hardware and various commercial embedded appliances. The focus is on platform portability, OS fundamentals and developer friendliness, rather than the end-user UI. The distribution is intended primarily for desktop graphical appliances, particularly thin clients (using the X11/XDMCP, ICA, RDP, and RFB graphics protocols). Although originally a network-booting OS, DIET-PC works well with various forms of solid-state persistent storage and hence is no longer strictly "diskless". The project uses QEMU virtual machines running Debian Linux (under Windows) as self-contained development environments, and hence may also be of interest for its unusual (non-x86) QEMU accomplishments.
Mail2sh makes it possible to carry out shell commands by email. Email is sent to a particular user on your host and the commands will be carried out if the user and password given matches ones in /etc/passwd. Commands are executed with the user's privileges, and combined with a PGP module ensures a certain level of security for use. Note that the system is not natively encrypted, so use of an encryption mechanism is highly recommended for security reasons.