Sending Multiple Probes - zmap/zmap GitHub Wiki

ZMap supports sending multiple probes to each host. Probes are sent as ethernet frames directly, so there is no guarentee of delivery in unreliable networks. Increasing the number of probes increases the number of hosts reached at the cost of increasing scan time. However, we find that the increase in scan time (~100% per additional probe) greatly outweighs the increase in hosts reached (~1% per additional probe).

• -P, --probes=n Number of probes to send to each IP/Port pair (default=1). Since ZMap composes Ethernet frames directly, probes can be lost en-route to destination. Increasing the --probes increases the chance that an online host will receive a probe in an unreliable network. This is contrasted with --retries which just gives the number of attempts to send a single probe on the source NIC.