Unable to access 10.2.3 16D17a machine over network
I believe I found a solution.

It appears that there may have been a change by Apple in how the Bonjour service handles router security.

I had changed my router to WPA2 due to needing to use the built in recovery system in the macOS bootloader, as it was not functional with WEP security.

I happened to notice that my AirPrint printer was no longer being seen on the network as well and I also couldn't ping it, so I changed the security back to WEP to test and Bonjour services started working again. I was able to print as well as access the apache server from my macOS machine from the iPhone across the network with the .local name.

Not being happy with having to use WEP again as it's far less secure than WPA2, I went about looking for a solution.

I have an Actiontec router used for my FiOS setup. It's a MI424-WR revision C with Firmware 4.0.16.1.56.0.10.14.4

Logged in and changed the following option:
Advanced -> IGMP Proxy -> Enabled 



Bonjour services appear to be functioning properly now with WPA2 enabled. Apache server, AirPrint, Remote.app, etc. All work fine.