2 separate Zyxel APs connected to Mikrotik on 2 ports (Eth2 & Eth3)
Scenario 1:
Chromecast → Zyxel NWA1123-ACV2 → RB2011UiAS ETH2
If I connect laptop via Zyxel NWA1123-ACV2 (any SSID, either 5 or 2.4 Ghz) there are no issues to cast (Chromecast is visible & accessible)
Scenario 2:
Laptop → Zyxel NWA1121-NI → RB2011UiAS ETH3 (same network as above , just another AP in a different part of the house connecting to another port on Mikrotik RB2011UiAS, both ports Eth2 & Eth3 are part of the bridge)
I can ping Chromecast, but it is not available to cast to.
Obviously multicast is being stopped at Mikrotik. It makes no sense, as ALL devices ARE on the SAME IP range
The only way I could get it working was as per this
Add the Chromecast to a static route. Use 239.255.255.250 as your network/Host IP, 255.255.255.0 as your netmask and the reserved IP address of the chromecast as the Gateway.
Why do you assume:
“Obviously multicast is being stopped at Mikrotik. It makes no sense, as ALL devices ARE on the SAME IP range”
It worked with MT and the first AP. What is new now is AP2.
Just to be sure you could plug AP2 in eth2, and try to reproduce.
Back to the issue, it may be related to ARP. IP-to-mac mapping. Do you have any arp filter along the way. Are all interfaces including your AP’s in arp=enabled mode?
I understand that you have your chromecast on ap1 and client sometimes on ap1 and ap2. AP1 - AP1 works, but AP1 - AP2 doesn’t.
What is new / extra in second case:
ap2
client itself
Have a look at their configuration wrt multicast processing.
AP2 is not an issue, as if I connect Chromecast to it I am in same situation. It is Mikrotik issue
(which I can sort as per first post, but do not think it should be so)