Suricata is an Intrusion Detection and Prevention (IDS/IPS) engine developed by the Open Information Security Foundation and its supporting vendors. The engine is multi-threaded and has native IPv6 support, file extraction capabilities, and many more features. It's capable of loading existing Snort rules and signatures, and supports many frontends through Barnyard2.
Ostinato is a network packet and traffic generator and analyzer with a friendly GUI. It aims to be "Wireshark in Reverse" and thus become complementary to Wireshark. It features custom packet crafting with editing of any field for several protocols: Ethernet, 802.3, LLC SNAP, VLAN (with Q-in-Q), ARP, IPv4, IPv6, IP-in-IP a.k.a IP Tunneling, TCP, UDP, ICMPv4, ICMPv6, IGMP, MLD, HTTP, SIP, RTSP, NNTP, etc. It is useful for both functional and performance testing.
RedWolf is a security threat simulator that tests security system effectiveness. Its threat generation capabilities include email, IM, malware, P2P, social networking, VoIP, DDoS, and many more. The guiding philosophy is that by generating realistic scenarios in a wide variety of categories, an auditor or organization can assess the effectiveness of network defenses. The scenario suite allows one to verify compliance with PCI-DSS, Sarbanes-Oxley, or HIPAA controls. RedWolf helps identify data loss risks and provides expert recommendations concerning risk mitigation. It reports present findings, recommendations, best practices, and blocking guidance in a straightforward, easily readable format. RedWolf also acts as a 'Red Team' agent, running drills to measure the readiness of your operations staff.