Added the following two lines to the device code (lines 2 and 3):
No different in behavior. On my laptop, I am using an IP address with the following command "telnet 192.168.0.1". I would think this connection would work even if no DNS is available. After all, I can ping 192.168.0.1 successfully. I would also think that no special routing is necessary since I am addressing the device itself and not trying to access some other IP address through the Photon's SoftAP.
So you believe what I'm trying to do should work? I'm starting to believe the Photon won't even route to itself while in SoftAP. A minimal routing table while in SoftAP doesn't sound hard, but not even routing to self sounds like a bug.
I added both of the following to the top of the Telnet Echo program, but I still receive the following from my laptop's telnet program when trying to telnet to Photon:
telnet: connect to address 192.168.0.1: Connection refused
telnet: Unable to connect to remote host
For reference, I am using the example code from the Particle Reference docs under TCPServer. I did comment out the lines referring to anything "Serial". Then I added the two lines mentioned above.
Only other thing I can think of is that my Photon does power-up connected to a Wifi Access Point. I press and hold the SETUP to make it temporarily lose connection to other WiFi.
Last comment: I wonder if it is because the call to TCPServer is in the setup() function. Maybe that TCPServer object needs to be initialized and started in loop(). I'll play with that. Would be helpful to confirm if this is supposed to work or not though.