blog

Capabale Chromecast Configuration (or, how I got Chromecast to work with Ubuntu)

So, I now own a Chromecast. Having acquired it while the Netflix promotion was in effect, I only ended up spending $11 on it. Not bad for a YouTube machine (the only reason I bought it since Roku still doesn't have YouTube support). I've been pretty happy with it thusfar as it turned out to be a great party tool, and the HDMI CEC support makes it really easy to throw YouTube videos on in the background, even if the TV is off.

However, one feature I was having trouble getting to work under Linux was tab casting. Using the Chromecast Chrome extension, one should be able to transmit the contents of a tab to a Chromecast on the local network. For some, reason, though, I was unable to do so. After some poking around, I determined that my firewall (ufw, the greatest misnomer of them all) was causing this. Since it was using a randomly assigned local port to establish the connection, simply opening a port wasn't the answer. Not to be deterred, I set about conquering this problem. Here's what I did.

  1. Find the Chromecast's MAC address. In my case this was a two-step operation...

    1. Launch the Chromecast app to determine the device's IP address.

      A screenshot of the IP address of a Chromecast desplayed within the Chromecast app.

      The IP address is circled in red.

    2. Ping the device and then check the address resolution stats.

      [aru@Ananke:~]$ ping -c 1 192.168.1.42
PING 192.168.1.42 (192.168.1.42) 56(84) bytes of data.
64 bytes from 192.168.1.42: icmp_req=1 ttl=64 time=1.66 ms

--- 192.168.1.42 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 1.669/1.669/1.669/0.000 ms

[aru@Ananke:~]$ arp -a 192.168.1.42
? (192.168.1.42) at d0:e7:82:7c:15:76 [ether] on wlan0

  2. Assign a static IP to the device. Configure your router to assign a static IP to the MAC address you found in the previous step. If you don't know how to do this, Port-Forward.com has some decent tutorials. You may have to restart your router after setting up this rule.

  3. Determine your local port range. In my case, since I'm using IPv4, I did the following: 

    [aru@Ananke:~]$ cat /proc/sys/net/ipv4/ip_local_port_range
32768   61000

    The two numbers are the lower and upper bounds of the local ports available for casting.

  4. Whitelist your Chromecast. Using the now-static IP address and your local port ranges, tell ufw to step off!

    [aru@Ananke:~]$ sudo ufw allow proto udp from 192.168.1.42 to any port 32768:61000
Rule added

Once you've done this, open up Chrome, click on the Chromecast button, and start tabcasting!

Chromecast extension screenshot.

As you can see, I don't use Chrome for very much.