Apple AFP not connecting

[MacEvansCB]

I have a simple home network consisting of a Mac Mini connected via cable to an RT-N56U router and another Mac Mini HTPC connected to the router via 5.0MHz wireless. The router is connected to the Internet via a TP-Link TC-7610 modem.

Both Macs connect to the Internet with no problems. But they won't talk to each other. I can ping the router and random Internet sites from both Macs, but both Macs cannot ping the other Mac in either direction. This makes me suspect the router. Does anyone know of any settings I need to check or change???

 

[ColinTaylor]

Are you pinging the MACs by IP address or name? Is the HTPC connected to the "normal" wireless SSID or are you using a guest network?

What firmware version are you running?

 

[MacEvansCB]

By IP address in the Terminal app.

The normal named SSID. See attached image.

3.0.0.4.380.7378 which, thru a lot of searching and a tech support chat, I think is up-to-date.

 

[MacEvansCB]

(sheepishly) Colin: I had my VPN connected to the Internet from the HTPC Mac. Sorry.

When I disconnected the VPN, I had full file sharing working from the wireless HTPC Mac, but I still can't connect the wired main Mac to the HTPC Mac. This matches the Terminal pings which show good from the HTPC Mac to the main Mac and bad from the main Mac to the HTPC Mac.

This is my original problem. Now I don't know if this is a router problem or a Max OS X problem. The HTPC Mac is running Mac OS X v10.11 Sierra and the main Mac is running OS X v10.9 Mavericks. I don't know if my main Mac being out-of-date by two versions is causing problems.