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.
Open DHCP Server is full fledged, all purpose DHCP server. It supports nearly all industry standard functionality. It supports both dynamic and static leases, multiple domains, multiple subnets, and relay agents. It also supports BOOTP and PXEBOOT. It allows user-defined options, which can be global, range-specific, or client-specific. DHCP ranges can be further filtered by MAC address ranges, Vendor Class, or User Class.
PacketFence is a fully supported, trusted network access control (NAC) system. It includes a captive portal for registration and remediation, centralized wired and wireless management, 802.1X support, layer-2 isolation of problematic devices, and integration with the Snort IDS and the Nessus vulnerability scanner. It can be used to effectively secure networks, from small to very large heterogeneous networks.
PacketFence Zero Effort NAC (ZEN) is a network access control (NAC) system. It supports registration of new network devices, detection of abnormal network activities, isolation of problematic devices, remediation through a captive portal, registration-based and scheduled vulnerability scans, VLAN isolation with VoIP support (even in heterogeneous environments) for multiple switch vendors, support for 802.1X through a FreeRADIUS module, wireless integration with FreeRADIUS, DHCP fingerprinting, and more. It consists of a fully installed and preconfigured version of PacketFence inside a VMWare image.
EtherApe is a GNOME/pcap-based etherman, interman, and "tcpman" clone. It displays network activity graphically. Active hosts are shown as circles of varying size, and traffic among them is shown as lines of varying width. It supports Ethernet, FDDI, Token Ring, ISDN, PPP, WLAN, and SLIP transports. It knows about VLANs, IP, IPv6, TCP, UDP, FTP, and a number of other protocols. Additional statistics windows will let you concentrate on protocols or nodes.
nss-pam-ldapd is a Name Service Switch module and Pluggable Authentication Module using an LDAP server. It allows your LDAP server to provide user account, group, host name, alias, netgroup, and almost any other information that you would normally get from /etc flat files or NIS, and allows you to do authentication to an LDAP server.
The WiKID Strong Authentication System is a highly scalable, secure two-factor authentication system. It is simple to implement and maintain, allows users to be validated automatically, requires no hardware tokens, has a simple API for application support (via Ruby, PHP, Java, COM, Python, etc.), supports multiple domains, and supports replication for fault tolerance and scalability. It also supports mutual /host and transaction authentication, wireless tokens only domains, locked tokens (to your PC), anti-keystroke logger keypad PIN entry, etc.
strongSwan is a complete IPsec implementation for the Linux, Android, Maemo, FreeBSD, and Mac OS X operating systems. It interoperates with with most other IPsec-based VPN products via the IKEv2 or IKEv1 key exchange protocols. The focus of the strongSwan project is on strong authentication mechanisms using X.509 public key certificates and optional secure storage of private keys on smartcards through a standardized PKCS#11 interface. A rich choice of modular plugins adds additional features like Trusted Network Connect or advanced cryptographical algorithms.
ENet for C# wraps the C-language ENet networking library. For games and other realtime applications, if you use TCP, old data can hold up newer data, even if it is no longer relevant (old positions, etc.). Your players will perceive any lost packet as a "lag burst". ENet supports multiple in-order streams of data, and allows you to decide on reliability on a per-packet basis. The library is useful for both client-server and peer-to-peer architectures.