rate

Specifies the desired transmit rate of packets, in units of packets-per-second. The following example will transmit at a rate of 100 packets-per-second.

# masscan --rate 100

This number can be very large, such as a billion:

# masscan --rate 1000000000

It won't got that fast, of course, but it can get up to around 10 million packets-per-second. Therefore be careful with how large a value you put here, because it can melt your network.

The rate is a floating point number. Therefore, you can transmit slower than one packet per second. The following example transmits at one packet every two seconds, useful for testing:

# masscan --rate 0.5

Nmap compatibility: Since nmap is synchronous, and masscan asynchronous, how rate is calculated is fundamentally different. Timeouts don't affect rate in an asynchronous system, for example. Thus, all the nmap parameters don't apply. However, we will treat the parameters --min-rate and --max-rate the same as rate.