I've bumped into the weirdest problem with dynamic DNS and Raspberry Pi.
Here's my setup:
- Raspberry Pi has IP address 172.16.1.xxx
- Raspberry Pi is in DMZ
- I'm using DynDNS to point whatever.dyndns.org at my Raspberry Pi.
Here's where things break down. If phone is on the same network as the Raspberry Pi and I go to 172.16.1.xxx, boom! the Raspberry Pi pops up. If I try going to whatever.dyndns.org while I'm on the same LAN as the Raspberry Pi, the browser says website not found.
Then, if I connect to cellular data and go to whatever.dyndns.org, the Raspberry Pi responds as if nothing was wrong. If I try the same from work or the WiFi at the coffee shop or from a friend's place, everything works OK.
Here's what's bothering me. Why can I not access whatever.dyndns.org from inside the LAN but I can from outside? What am I doing wrong here?
EDIT: My router/gateway is an Actiontec V1000H provided by my ISP. I have to use this since I'm on a fibre optic connection. (I asked them for a DSL connection over twisted pair. They said all new connections are FO.)
UPDATE: So it is my router. It does not support NAT loopback, and it does not support bridged setup. I'm going to investigate if I can use an off-the-shelf router. Looks unlikely. :(