diff --git a/README.md b/README.md
index d19855a..62bf375 100644
--- a/README.md
+++ b/README.md
@@ -13,6 +13,10 @@ Thanks to all [contributors](https://github.com/sbilly/awesome-security/graphs/c
 * [justniffer](http://justniffer.sourceforge.net/) - Justniffer is a network protocol analyzer that captures network traffic and produces logs in a customized way, can emulate Apache web server log files, track response times and extract all "intercepted" files from the HTTP traffic.
 * [httpry](http://dumpsterventures.com/jason/httpry/) - httpry is a specialized packet sniffer designed for displaying and logging HTTP traffic. It is not intended to perform analysis itself, but to capture, parse, and log the traffic for later analysis. It can be run in real-time displaying the traffic as it is parsed, or as a daemon process that logs to an output file. It is written to be as lightweight and flexible as possible, so that it can be easily adaptable to different applications.
 * [ngrep](http://ngrep.sourceforge.net/) - ngrep strives to provide most of GNU grep's common features, applying them to the network layer. ngrep is a pcap-aware tool that will allow you to specify extended regular or hexadecimal expressions to match against data payloads of packets. It currently recognizes IPv4/6, TCP, UDP, ICMPv4/6, IGMP and Raw across Ethernet, PPP, SLIP, FDDI, Token Ring and null interfaces, and understands BPF filter logic in the same fashion as more common packet sniffing tools, such as tcpdump and snoop.
+* [passivedns](https://github.com/gamelinux/passivedns) - A tool to collect DNS records passively to aid Incident handling, Network Security Monitoring (NSM) and general digital forensics. PassiveDNS sniffes traffic from an interface or reads a pcap-file and outputs
+the DNS-server answers to a log file. PassiveDNS can cache/aggregate duplicate
+DNS answers in-memory, limiting the amount of data in the logfile without
+loosing the essens in the DNS answer.
 
 ### Full Packet Capture / Forensic