Tor is a network of virtual tunnels that allows people and groups to improve their privacy and security on the Internet. It also enables software developers to create new communication tools with built-in privacy features. It provides the foundation for a range of applications that allow organizations and individuals to share information over public networks without compromising their privacy. Individuals can use it to keep remote Websites from tracking them and their family members. They can also use it to connect to resources such as news sites or instant messaging services that are blocked by their local Internet service providers (ISPs).
GNUnet is a peer-to-peer framework with focus on providing security. All peer-to-peer messages in the network are confidential and authenticated. The framework provides a transport abstraction layer and can currently encapsulate the network traffic in UDP, TCP, HTTP, HTTPS, or direct 802.11 (WLAN). GNUnet supports accounting to provide contributing nodes with better service. The services built on top of the framework include anonymous file sharing and a virtual network providing IPv4-IPv6 transition via protocol translation over the P2P network.
Asterisk is a hybrid TDM and packet voice PBX (Private Branch eXchange) and IVR platform with ACD functionality. It acts as middleware between the Internet (IAX, SIP, MGCP, Skinny, H.323), telephony channels (like Zaptel, T1, PRI, E1, FXO, FXS, VoIP, VoFR, ISDN, modems, Internet Phone Jack, etc.), and applications (like voice-mail, conferencing, directories, MP3 players, intercoms, etc.). It has many advanced features such as a codec translation API. The base distribution includes several channel backends, as well as applications. However, the beauty of Asterisk is its ability to be extended using its APIs, dynamic module loader, and AGI scripting interface. End users can even write their own applications that run on the system in C or any scripting language of their choice.
MailScanner is an email virus scanner, vulnerability protector, and spam tagger. It supports the Postfix, Sendmail, Exim, Qmail, and ZMailer MTAs, and the Sophos, McAfee, F-Prot, F-Secure, CommandAV, InoculateIT, Inoculan, eTrust, Kaspersky, Nod32, AntiVir, BitDefender, RAV, Panda, DrWeb, ClamAV, and other anti-virus scanners. It uses SpamAssassin for highly successful spam identification, and is designed to handle denial of service attacks. It will detect password-protected zip files and apply filename checking to their contents. It is very easy to install, requires no changes at all to your sendmail.cf file, is designed to be lightweight, and won't grind your mail system to a halt with its load. It can be integrated into any email system, regardless of the software in use.
PasTmon (Passive Application Response Time Monitor) passively monitors your application servers, measuring and reporting user response times, throughput and congestion. It currently works with HTTP, telnet, rlogin, rsh, FTP (control channel), SMTP, POP3, and IRC. Measurements are recorded in a PostgreSQL database and are presented graphically via a PHP Web front-end using R statistical analysis scripts to create the plots.
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.
L7-filter is a packet classifier for Netfilter that identifies packets based on application layer (OSI layer 7) data. This means that it is able to classify packets as HTTP, FTP, Gnucleus, Kazaa, etc., regardless of ports. It complements existing matches that classify based on port numbers, packet length, TOS bits, and so on. Combined with Linux QoS, it allows for full layer 7 packet shaping.
Xplico is an IP traffic decoder that extracts data from an Internet traffic capture. From a pcap file, it can extracts each email (POP, IMAP, and SMTP protocols), all HTTP content, VoIP calls (SIP, RTP, H323, MEGACO, MGCP), IRC, MSN, and so on. It isn't a packet sniffer or a network protocol analyzer, but rather an IP/Internet traffic decoder or network forensic analysis tool (NFAT).
The GNU Gatekeeper is a free H.323 gatekeeper based on the OpenH323 project. You can use it to manage a Voice-over-IP network and let endpoints (e.g., Netmeeting) communicate through symbolic names. It also has an external interface for billing and other applications. It runs on a number of Unix versions (including Linux and Solaris) and Windows.
C++ Sockets is a cross-platform C++ wrapper for BSD-style sockets. It implements the TCP, UDP, ICMP, and SCTP transport layer protocols. Implemented application layer protocols are HTTP/HTTPS (using OpenSSL), SMTP (server), and Ajp/1.3 (server). Features include transparent SOCKS4 client support and asynchronous DNS. Included in the library are a number of HTTP client functions such as GET/PUT/POST, and also Web server framework components.