By default, this systemd unit files exposes port 5050 to every interface. ZFS Receive listens on this port, and process the data without any encryption.
Be aware that it's not meant to be exposed on an insecure network, such as internet.
Edit zfs-recv@.service file.
You'll want to edit the zfs recv -F MainVolume/SAN part to specify your dataset in the receiving system.
In order to listen to only one interface, edit the [Socket] section of zfs-recv.socket.
Add a new line: BindToDevice=ens192 (or whichever interface you want to bind).
Copy both socket and service unit files to: /etc/systemd/system/.
In the target system, enable and start the socket:
systemd enable --now zfs-recv.socket
There's no need to start the service, the socket will take of that when there's an incoming connection. If multiple connections are requested, multiple services will be started.
In the source system, you can use netcat:
zfs send dataset@snapshot | nc myserver.domain.com 5050