Hi,
Even though the LTM doesn't have the subnet specified as a self IP and VLAN, it has the public subnet routed to it.
I have virtual servers and NAT/SNAT for those IP addresses, and I see the F5 responds to the ARP requests for those addresses.
I just think it would be a good feature to extend the transparent health check type to make it possible to originate from specific IP address other than the self IP.
I tried to use ping, tracepath, traceroute to use a different originating IP address, but it was not possible. I will look into the netcat that you proposed.
Regards,
Zoltan