ZMap

ZMap is a fast single packet network scanner designed for Internet-wide network surveys. On a typical desktop computer with a gigabit Ethernet connection, ZMap is capable scanning the entire public IPv4 address space in under 45 minutes. With a 10gigE connection and PF_RING, ZMap can scan the IPv4 address space in under 5 minutes.

ZMap operates on GNU/Linux, Mac OS, and BSD. ZMap currently has fully implemented probe modules for TCP SYN scans, ICMP, DNS queries, UPnP, BACNET, and can send a large number of UDP probes. If you are looking to do more involved scans, e.g., banner grab or TLS handshake, take a look at ZGrab, ZMap's sister project that performs stateful application-layer handshakes.