We are pleased to announce the 9th NDN 2017 Retreat: an opportunity to discuss the application environments, the NDN software platform and testbed, and focus on some specific areas such as security. The retreat itself is on Thursday and Friday, while NDN hackathon will be held on Staturday and Sunday (project signup will be done on Friday afternoon)The primary goals of the retreat are:Gain new insights and ideas for NDN trust and security mechanism in the context of the network environmentsFind new design directions for the pilot applications in the proposed network environmentsSee active involvement by all attendeesWe wish to focus our interactions and discussions on making problems of security within the targeted NDN-NP application environments concrete and to find and flesh out application specific security problems. We hope to focus on student interaction and new ideas related to NDN NP applications in a retreat-style setting. The NDN project uses current and future applications to drive the development and deployment of the architecture and its supporting modules, to test prototype implementations, and to encourage an iterative cycle of hands-on experimentation, evaluation, and design. So, we particularly encourage attendees to prepare in advance of the retreat: install all prerequisites for developing and running NDN applications.