Multicast routing, what do I need to do?

I read about allowing traffic to or from (can't remember) in the firewall section to make multicast routable across different subnets, but I'm not sure how it's done.

The two subnets in question are LAN1 ( and LAN2 (, which reside in the same firewall zone, how do I set in the firewall section to allow devices in either subnet to discover services in the other? Thank you.

Have a look here.


Thank you trendy for pointing me the right direction, I'll try the suggested solution and report back.

I guess there's some limitation with the iptables version 1.8.3 that comes with the Openwrt, while excuting

"iptables -t mangle -A PREROUTING -i br-lan -d -j TTL --ttl-inc 1
iptables -t mangle -A PREROUTING -i br-lan2 -d -j TTL --ttl-inc 1",

I got the message
iptables v1.8.3 (legacy): unknown option "--ttl-inc"

any suggestions? Thank you!

opkg list-installed | grep iptables ?

the output is
iptables - 1.8.3-1

You need also ipopt

Thank you! I just did it.

From my test, even without the TTL hack, I can discover DLNA across subnets, and now with the help of it, I'm still not seeing chromecast targets on the other side, do you have experiences with the chromecast "issue"?

I don't have experience with Chromecast, but as with any problem, you'll have to troubleshoot it.
First of all verify that the rules you added have some hits (`iptables-save -c | grep TTL)
Verify with tcpdump that the packets received are relayed to the other interface.


I appreciate the help trendy, many times you've given me the right answers, I'll dig deeper.

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