Guess WIFI no longer allows chrome cast

[franco2018]

We use to be able to have to laptops on guess wifi to chrome cast but it's no longer working 

I believe it stops working a week ago

[PhilipDAth]

What changed in the last week?  Firmware upgrade?  WiFi Firewall rules?  Something else?  You can check the Organization/Change Log.

Is the guest WiFi bridging onto the VLAN where the notebooks are located that are trying to do the casting?

[DillonofAnch17]

The change log is your best friend! Also what access points are you utilizing and is there firmware up to date?

We have had major chrome issues in our environment and the latest firmware seemed to fix that across the board

[franco2018]

The changelog does not show anything changed. It is at the latest firmware, and I follow this vlan config

https://documentation.meraki.com/MR/Client_Addressing_and_Bridging/VLAN_Tagging_on_MR_Access_Points

What else I can do SUpport is extremely slow I sometimes on hold for hours and when the open case they can take a days to response

Also kindly note that I can ping from guess network to tv network I can not chrome cast

There must be something blcking it

[jdsilva]

Please elaborate on what exactly is not working. There are a few steps involved in casting to a device, and a failure at any one of them can mean drastically different problems and solutions.

[franco2018]

The guess wifi use to be able to chrome cast to tv wifi and it not finding any device at this time

The guess network can ping to the tv wifi but will not able to chrome cast since can not find devices.

Guess was able to find these devices and chrome cast to them two weeks ago.

[jdsilva]

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@franco2018 wrote:

The guess wifi use to be able to chrome cast to tv wifi and it not finding any device at this time

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So you're saying that if you open a casting enabled App that the chromecast icon does not appear in that app?

Do you have SSID's for both the tv network and the guest network?

[franco2018]

The chrome browser is able to cast to devices that have builtin or  a chromecast  device that is connected to another device like a tv

Two weeks ago Any laptop connected to guess wif when clicking on chrome cast would see the chromecast devices both builtin and the chromecast device that is attached to the tv

Currently, when clicking on that option it does not display any devices

The wifi that these laptops are connected to is guess wif the TVs are connected to wifi called tv

Two or three weeks ago everything worked. Currently, the guest wifi  laptops can ping to a tv that connects to tv wifi

However, it can not chrome cast to that same tv 

[jdsilva]

Is the Guest SSID and the TV SSID bridged to the same VLAN? Or different VLANs?

[franco2018]

different vlans  It has stayed on different vlans .. two vlans should be able to configure so that you can allow and disallow the traffic you want between the two of them.

It may be that is the issue of how do I allow the two vlans to allow chrome cast between the two. Remember that these two vlans can ping to each other

[franco2018]

different vlans  It has stayed on different vlans .. two vlans should be able to configure so that you can allow and disallow the traffic you want between the two of them.

It may be that is the issue of how do I allow the two vlans to allow chrome cast between the two. Remember that these two vlans can ping to each other

[jdsilva]

OK, so I'm not clear on how this ever worked. Chromecast dongles advertise themselves on the network using the mDNS protocol. mDNS is a multicast protocol and by default multicast packets _will not_ move between VLANs. A client in your Guest VLAN cannot see the mDNS advertisements sent on the TV VLAN.

Additionally, when a client opens a casting enabled app it may also send a an mDNS request looking for casting enabled devices, to which they will unicast a reply. However the same problem exists in that the mDNS request will not move between VLANs.

The above info applies only to the discovery phase of casting. Once a client has a list of casting enabled devices, and a user selects a device to cast to, the transaction changes to unicast using the CAST protocol. 

So in the end I'm not able to explain how this ever worked. If you have two SSIDs and two VLANs with clients and Chromecasts each on their own, then this should not have ever worked. The only way it could have worked is if something was routing (or maybe accidentally bridging???) the mDNS multicast packets between VLANs. 

I agree with the other people above that something must have changed on your network. But what that is I'm still not able to say. 

[franco2018]

then how do you explain this url?

https://documentation.meraki.com/MX/Other_Topics/Configuring_Bonjour_forwarding_for_the_MX_Security_...

[jdsilva]

I explain that as Bonjour and CAST are not the same protocol and are not related in any way.

[franco2018]

note if I follow the instructions and leave the browser on for about 1 minute it will see the devices

the issue if I shut down the browser and relaunch it .. again it takes about a minute and it will see them

I feel there must be a way to get this to work and make it work much more consistent and quicker

[jdsilva]

Interesting. That's good info. I believe the Chromecasts send advertisements once a minute if I remember correctly. Usually you see them in the list faster than that because the client sends out the request that I described above... This would seem to indicate that the mDNS advertisements from the Chromecast reach the client, but the mDNS requests from the client do not reach the Chromecast.

Perhaps if you run a packet capture of the mDNS traffic you may be able to determine why you (possibly) have unidirectional mDNS traffic. 

[cta102]

Due to the lack of clarity (to me anyway):

When you say Chromecast you mean actual Chromecasts from Google and not just devices using the 'Google Cast' protocol (there is a couple of reasons.)
I'm assuming that the Chromecasts are connecting via Wi-Fi (rather than the optional Ethernet connection)
The Chromecast and Guest are on different SSIDs.
The SSIDs are in bridge mode and are on different VLANs


As has been pointed out Bonjour forwarding is of no benefit to a chrome cast, Bonjour is essentially Apple only.

Not every manufacturer seems to implement the protocols properly properly both TiVo and Samsung devices behave quite differently to an actual Chromecast.

If you really need to use something along the lines of Avahi to permit the protocol to traverse VLANs.

Chromecasts also use an ultrasonic signal to advertise their existence and to permit guests to connect was this previously used?

Has there been any recent Chromecast firmware updates?