Serve files to guests phones at your event via Wi-Fi

Posted by tomachi on May 13th, 2012 filed in Technology

The problem: you want to give a free MP3 audio file to your guests at your event and would like something more scalable, faster, cheaper and easier than giving out CDs and/or loading USB sticks manually, and would prefer the file to end on their smartphone anyhow where they can listen on headphones quickly.

Proposed solution: Serve the files via locally hosted laptop web server on a private wireless network (WLAN). Users download to their iPhone/Android/laptop from the free wireless network. No internet connection is needed and download is full speed.

Users see’s the following QR Code for http://freetune.funk.co.nz/ to scan:

Visit http://freetune.funk.co.nz/ on your phone for MP3 Download

Visit http://freetune.funk.co.nz/ on your phone for MP3 Download

Plan:

  • Laptop (in our case a Mac) running:
    • Locally modified hosts file with entry for freetune.funk.co.nz pointing to localhost (say 10.0.0.100)
    • Apache setup to serve the file with a local website running on the laptop
    • Sharing it’s non-existent “internet” via DHCP over the ethernet port
  • Wi-Fi router (I’ll use a WRT54GL linux router) set to:
    • Open network no password (or publish password inside event)
    • Laptop is connected to as the upstream WLAN ethernet port and is default gateway
    • Clients phones and laptops connect to this router
    • Hopefully the router can handle ~200 clients connecting to it through the evening
  • Business card printouts containing a QR Code for http://freetune.funk.co.nz/
  • Instructions for users of iOS and Android to scan the code or visit http://freetune.funk.co.nz/
  • Backup real DNS entry
    • on live internet for your private LAN IP (say 10.0.0.100 or 192.168.1.1)
  • Captive Portal idea:
    • Ideally an extra tweak to DNS make every lookup for any domain go to this IP address
    • Apache setup to redirect all requests to the private IP
The backup public DNS entry is just in case your guests get online somehow but still on your LAN, the public DNS will still tell them to go to the private IP address you’ve setup. This could maybe happen your laptop picks up another WLAN and you connect to it halfway through the event. Normally your hosts file changes would block any DNS lookups going through is my guess, but at this time I don’t know if my Mac will serve the false DNS lookups to the users via wired ethernet or try to use the one given from the new 2nd network.

 

Laptop web-server will be plugged into the "Internet" port, left side

Laptop web-server will be plugged into the "Internet" port, left side

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