OPNsense Forum

Archive => 20.1 Legacy Series => Topic started by: jhenderson0107 on May 01, 2020, 01:01:07 AM

Title: Multicast support
Post by: jhenderson0107 on May 01, 2020, 01:01:07 AM
A Linux-based hardware product that I manufacture utilizes multicast to send messages to applications on a local lan.  Clients cast to IP 234.5.6.7 port 8910 and servers subscribe to these messages to identify available clients.   

This all worked fine when using an Asus TM-AC1900 router on my local network.  But, I recently upgraded to an OpnSense -based router (running on a Qotom embedded PC) and I can't figure out how to configure OpnSense to propagate these multicast messages.  I wrote the client and server code above and my understanding is that the router is responsible for this function.  But, I'm inexperienced with multicast and sophisticated routers like OpnSense, so I'd appreciate any guidance that you can provide. 

Title: Re: Multicast support
Post by: hbc on May 01, 2020, 09:35:03 AM
Multicasts are stopped at broadcast domains. Each router is a border of a broadcast domain. Broad-/multicast will not pass without explicit configuration. For opnsenses exist several plugins to forward/proxy broad-/multicasts.

Search plugins for mdns-proxy, igmp proxy and someone currently develops a generic udp forwarder (search this forum). Plugin depends on your multicast protocol.
Title: Re: Multicast support
Post by: jhenderson0107 on May 02, 2020, 01:21:17 AM
hbc -

Thank you for responding.  I will investigate your suggestions. 
Title: Re: Multicast support
Post by: marjohn56 on May 02, 2020, 08:30:27 AM
Are the server and client on different LAN segments, you don't say. If they are on the same LAN then the router is irrelevant.