Raspberry Pi Webiopi Site Host - Cannot connect while on local address. Outside network works fine

AT&T requires the use of one of their Gateways and none of them do NAT loopback well.  If your router does NAT loopback, then that would solve your issue better than the DNS scheme.

There are many articles here that cover it, but mainly:

1) Connect your router's WAN port to a LAN port of the Gateway, and set it to obtain its outside address via DHCP (a fairly normal setup)..  Set its LAN site up like you want your home network to be addressed.  It's best if you don't use the same private subnet for the Gateway's LAN and the Router's LAN, so change the Gateway's if it has the IP range you want the Router to have.

2) Log in to the configuration portal of the Gateway and (under Firewall) set up IP Passthrough / DMZplus mode (same thing, name depends on the Gateway brand) for your router.  

3) Turn off both.  Turn on the Gateway, then the router.  

4) The router should come up with a public external IP address (same as the Gateway's)

5) Remove any port forwarding on the Gateway

6) Set up your port forwarding on the Router.

We're here to help, @tscracraft!

To further troubleshoot this, could you provide us with the specific reason why you're having connect to your outside address of (https://soc.att.com/2pybsdb)?

Let us know- we look forward to hearing back from you!

Donovan, AT&T Community Specialist

Hello Donovan,

I am using the raspberry pi to control my garage door opener.  I use a browser on my phone to connect to the html server (hosted by the raspberry pi, listening on port 8000).  If I pull up to my house (outside of wifi range) I have to connect to the external IP to connect to the raspberry pi.  However, if I get close enough, the phone connects to the wifi and then I have to connect to the internal IP address.

The port on the external IP should be forwarded to my internal.  So, regardless if I am on the wi-fi or mobile, it should end up at 192.168.0.xxx:8000.  Unfortunately, it doesn't work.

The AT&T Gateway firmware doesn't do NAT loopback well, if at all.  So, trying to use the external address while in your network is going to be problematic.  I would suggest that you set up some Dynamic DNS for external and an internal DNS for your local network, but... um, you can't change your DNS on the gateway, so you would have to get another router involved to do that.  And you could still have issues with stale DNS caching since you're sitting at the border of your network and could get the DNS resolved via cell network (external), then try to use that once Wi-FI connects (or vice versa).

This is quite disappointing.  Could you recommend another modem that I could purchase?  I do have another router I could add into the mix if needed.  Can you explain how to set it up?

@tscracraft.

As stated by @JefferMC, setting up your 3rd party router on the network may solve this for you, and they listed out some great steps to follow.

We'd recommend following the steps to see if hooking up that router allows you to connect your garage door opener.

Let us know if this solution works for you!

Ramses, AT&T Community Specialist

Hello Ramses/@ATTCares.  Setting up the IP passthrough worked as @JefferMC suggested.  I had a slight problem with the previous DHCP lease time, but I just factory reset the gateway, then reconfigured everything.  Working as expected now.

Thanks for letting us know you got it figured out, @tscracraft.

If you have any other questions or concerns, feel free to post on the forums.

Thank you for choosing AT&T!

John, AT&T Community Specialist

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@tscracraft wrote:

Hello Ramses/@ATTCares.  Setting up the IP passthrough worked as @JefferMC suggested.  I had a slight problem with the previous DHCP lease time, but I just factory reset the gateway, then reconfigured everything.  Working as expected now.

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Great!  Glad to hear you got it working.