Revised: August 19, 2014 Discovery of networked National Instruments devices (targets) by other devices (hosts) requires bi-directional communication between host and target. By default, National Instruments devices do not have communication restrictions. However, devices that are not produced by National Instruments may use firewall software as a security measure to restrict communication. National Instruments network device discovery requires access to the following ports. Port Protocol Description 5353 UDP Discovery of devices using the multicast Domain Name System (mDNS) protocol 44515 UDP Discovery of legacy devices 1 in safe-mode when a routable IP address is not known 44516 TCP Discovery of legacy devices 1 in safe-mode when a routable IP address is known 44525 UDP Discovery of legacy devices 1 in run-mode 1 This document refers to targets running the PharLap or VxWorks operating systems as legacy devices. For additional information on preparing systems for network communication with National Instruments devices, refer to the Configuring Software and Hardware Firewalls to Support National Instruments Products whitepaper.