Wireless cast & SMB broadcast across subnets

Hi all

  • Have two subnets lan (eth0.1 & wireless) & lab (eth0.3) with their own /25's (seperate VLANs untagged)

  • Wireless casting & SMB broadcast (DNS name display on xbox VLC) only works if all devices are on the same network, which is expected behaviour due to multicast I believe.

  • I'm wanting for wireless casting & SMB broadcast to work across the subnets.

I can't possibly be the only one with this use-case, however havent been able to figure out to get this to work.

Appreciate your thoughts & guidance.


As far as I know there are solutions for commercial products only which you can buy from e. g. cisco or hp.
In theory IP multicast could be a solution. But that depends on the software you are using. I don't have any experience with this.
Maybe this solution is working for other routers/OpenWrt (with modifications ofc) as well:

Thanks pwned

Im just surprised no one else in the oenwrt community is using a similar setup and found a way to get casting & smb share working across different internal networks.

Well, the thing is you usually do subnets for a reason (performance, better organisation, security). Imagine every client (clients initiating broadcasts!) would be allowed to broadcast to any subnet. If this would be allowed each client could broadcast any address in the internet also. Nobody want that so it is forbidden by default to route broadcast traffic across subnets. So this is OpenWrt default behaviour.

I don't know much about how smb is communcating (netbios, wins, broadcasts). But you should be able to access if you enter IP address directly into windows explorer or any other application e. g. kodi. Therefore routes and firewall (smb ports) have to be configured correctly on each subnet/router. And I'm not sure if Windows or XBox firewall is accepting traffic from different subnets.

Not commenting on default behaviour, that is well understood.

Plenty of scenarios where you would want multicast across subnets, and how to keep it limited to lan side.