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Chrome Browser can not find Chromecast & ChromeCast Ultra on Local Network with Fortigate Firewall


Recently I came Across wired problem, Laptop with google chrome can not find and cast to Chromecast dongle on our office meeting room although both devices were on the same network with the same IP range and I could ping the Chromecast IP ! It just didn’t work 🙁  Cromecast ultra have wire connection as well, That didn’t work as well.  First to blame was the Fortigate firewall as it is was immediate suspect to block all kind of traffic (although it is on the same Subnet -> layer 2 communication ), This are the recommended setting on Fortigate for support in Chromecast ( )  :

The FortiGate needs to be configured to not adjust TTL:

config system settings
set multicast-ttl-notchange enable

Multicast policies must be configured (this is where access can be restricted):

config firewall multicast-policy
edit 1
set srcintf “chromecasttest”
set dstintf “employeeWifi”
set srcaddr “all”
set dstaddr “all”
edit 2
set srcintf “employeeWifi”
set dstintf “chromecasttest”
set srcaddr “all”
set dstaddr “all”

With the above configured the Chromecast should be discovered by wireless/wired clients on other Subnets.

 For me that didn’t work as well , To check if this was just a problem with chrome browser I have install VideoLAN as it have Chomecast Feature build-in, After installing VLC from  , you can see the option for casting video :
And its works !!! yet from the chrome browser on the laptop it still didn’t  !!! Turn out Chrome browser only search for Chromecast on Private Networks IP’s . it is using RFC1918/RFC4193 which meens:


RFC1918 name IP address range Number of addresses Largest CIDR block (subnet mask) Host ID size Mask bits Classful description[Note 1]
24-bit block – 16777216 ( 24 bits 8 bits single class A network
20-bit block – 1048576 ( 20 bits 12 bits 16 contiguous class B networks
16-bit block – 65536 ( 16 bits 16 bits 256 contiguous class C networks

As this was our office network with alot of VLAN’s it was using different Subnet from the above there for google chrome broswer didn’t find the Chromecast as it didn’t search on that Subnet, you need to allow the browser to search on all the ip’s of the computer:

1. Ensure that you’re on the latest version of the Chrome Browser.
2. Open a new tab in Chrome.
3. Type or copy/paste chrome://flags/#load-media-router-component-extension into the address bar.
 4. Find  “Connect to Cast devices on all IP address” and choose Enabled .
5. Re-lunch Chrome.
Your Chromecast & Cromecast Ultra should now be discovered by Your PC or Laptop

Good Luck

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