--parallel-max-host

When asked to do parallel transfers, using --parallel, this option controls the maximum amount of concurrent connections curl is allowed to do to the same protocol + hostname + port number target.

The limit is enforced by libcurl and queued "internally", which means that transfers that are waiting for an available connection still look like started transfers in the progress meter.

The default is 0 (unlimited). 65535 is the largest supported value.