I just wanted to share a trick I used during a business trip this week.
This is a typical problem. You go into a free WiFi service hotel but guess what.. WiFi isn't protected but you need to be able to enter login and password through a browser to gain internet access. Obviusly, a hard job for the CC dongle unless...
Step 1 - Run CC setup on your mobile, tablet,.. The only reason you're doing this at this point is to find out the dongle MAC address.. Write down the CC MAC address (if you keep it, you may skip this step nex time).
Step 2 - The "hard part". Open your laptop, disconnect it from the Wifi network if connected and edit your Wifi network adapter settings. Find the option where you can change the MAC address (you may read something like 'Clone MAC' or something similar). Enter the CC MAC here and save your edits.
Step 3 - Connect your laptop to the netwok and browse any page so get asked for login/pass on the brower. Once you receive the confirmation and browsing is possible, the hotel router is allowing your MAC and IP to browse out of the "walled garden".
Step 4 - Start your chromecast, and run it as if it were a regular Wifi network. Make sure you disconnect your laptop from the network, before the CC actually connects to the hotel network. That will make the hotel router continue its authorization for that MAC address to get access to the internet.
Step 5 - If you see on the screen that chromecast connected to the network but can't access the internet; you did something wrong. Otherwise, you got it!.
Sep 6 - Launch Youtube on your phone/tablet and cast from youtube app first. For some reason, sometimes Plex can't find the chromecast at first. Stop youtube and switch to Plex. It should now find Plex as a player and work as fast as the network works.
Hope you can use and enjoy this!!
PS: Obviusly, there are more issues that may prevent you to use CC at the hotel. Most typical one is device isolation which makes not possible direct connectivity from your phone to the CC so your phone can't actually send the URL to start the streaming.