I'm an Android developer and often my applications require server-side code. I typically use Ruby on Rails for the web app, and during development will run the server on my local machine (Mac OS X) with WEBrick. In the morning when I get to the office, I'll run ifconfig in the console to see what IP my laptop has been given that day. I'll use that IP in my Android app when making requests to the web app in question.

This all works fine, when I'm in my office.

When I get home, I attempt to do the same thing, find my laptop's IP via ifconfig, set it in my app's config file, but the destination can never be found. To exclude my app from the set of hurdles, I attempt to visit the web server IP (e.g., http://192.168.1.4:3000) from my phone's browser, and it cannot connect. If I try from my laptop, which is running the web server, it works fine. If I try from another machine, on the same network, it also is unable to connect.

Given this, I think I've narrowed it down to some kind of configuration in my home network, but I frankly have no idea what the cause could be. I don't have anything special at home, your basic Verizon FiOS router/modem with everything connected via Wi-Fi (Wi-Fi for both phone and laptop at work as well, fyi). I've tried disabling the firewall on my Verizon router, enabling port forwarding, and just about everything else I could do for port 3000, and nothing has changed.

Dear Server Fault geniuses, please help a poor developer out. :)

Edit:

Some follow up items to add. My Mac's firewall is not active, and all incoming requests are allowed. I've also verified on my phone and laptop, that they're on the same network (192.168.1.4 Mac, 192.168.1.9 Phone). I have no idea why this isn't working.

Edit 2:

I went into System Preferences, enabled Web Sharing, and tried to view the website from my phone and it didn't connect. So it's not WEBrick or related to Rails. The firewall on my machine is off and the firewall on my router is off.

Edit 3:

Some progress. I set up port forwarding for port 3000 to my laptop, found the external IP, and used that and it connected fine. So, there's definitely something not quite set up correctly on my internal network.