The following is my current setup:
Apple MacBook Pro (MBP) with macOS 10.14.4 with internet sharing from wifi to ethernet enabled as well as synergy pro running in server mode as a network-enabled keyboard & mouse sharer/switcher
Western Digital MyCloud Home (MCH) 4TB connected to MBP's ethernet port which provides a Time Machine compatible, apple file sharing protocol based network volume, for which the DNS mapping of the MyCloud-XXXXXX.local domain onto the DHCP assigned IP address of the MCH device is done via a zeroconfiguration protocol that broadcasts it's available services through out it's local area connection, which in turn is compatible with Apple's OS zeroconf variant known as Bonjour as well as Linux and Windows (as long as a Bonjour-compatible client is installed in windows) OSes.
Hewllett Packard ProBook (HPB) 4440s with dual boot Ubuntu 18.04 & Windows 10 Pro both operating systems have been configured and verified to communicate with bonjour via synergy pro running in client mode which relies on bonjour/zeroconf and an ethernet cable used as the uplink to the internet, the ethernet port on the linux OS has been set to share via wifi Hotspot.
The MBP then connects to the HPB's wifi hotspot while the HBP is running Ubuntu.
Therefore the network diagram from internet to mycloud home is represented by the following:
Internet <--via ethernet--> HPB <--via WIFI--> MBP <--router mode enabled via Ethernet--> MCH
On the Ubuntu partition of the HPB, I have enabled the Deja Dup backup tool to work with the MCH via it's zeroconf address as the storage location which works out to be:
/run/user/1000/gvfs/afp-volume:host=MyCloud-XXXXXX.local,user=anonymous,volume=TimeMachineBackup/path/to/folder
where the six consecutive 'X' are substituted for the device identifier and '/path/to/folder' is substituted for the folder that I wish to save the duplicity created tar.gz files.
This works when the MCH is connected to an ethernet port that is either directly managed by the a wifi access point (WAP)/modem/router or connected in bridged mode with respect to the WAP/modem/router. However because the automatic discovery packets associated with the MCH's zeroconf protocol are not visible by devices outside of it's "network" which in this setup, due to the way that macOS internet sharing is implemented in router mode (with DHCP/NAT enabled and therefore a distinct subnet and IP range) is limited to the MBP and no other device.
The reason that I have connected the MCH directly to the MBP is that the Mac is my primary workstation, therefore it produces the most content that needs backing up and the connection between MCH and MBP I want to have the least latency and highest priority/reliability. Thus the connection between HPB and MCH is for the most part auxiliary and not critical to my workflow, however it is still desirable.
I have already read how it is impossible to bridge an ethernet connected device onto a wifi network segment as explained in the following link:
Share internet as Bridge instead as a Router using PFCTL (OS X)?
I would like to know if there is any work around or solution (even if it's not elegant) such as to get the MCH zeroconf protocol to work across all network segments that I choose, at least those segments of the network that are under my control because I created/configured them to a point far beyond a standard use-case.
P.S. Any help would be greatly appreciated, and thank you in advance.
