[puterboy2]

I have my host network 192.168.1.X on br0 and an IoT network on a VLAN on br1 on 192.168.100.x, with a device on 192.168.100.3
- br0 can pass traffic freely to br1
- br1 is locked down except for DNS, mDNS, and UDP ports 9999, 20002
- mDNS resolver and repeater are enabled

All the following work properly
- I can avahi-browse from br0 to see the devices on br1
- Devices on br1 have DNS service and can access the Internet
- I can ping devices on the br1 network from br0
- I can unicast from br0 to any IP address & port on br1, e.g, "echo hello | nc -u 192.168.100.3 20002" and see the packets in Wireshark on 192.168.100.3


HOWEVER, I can't seem to broadcast to br1 (even with the firewall disabled)
e.g., "echo hello | nc -u -b 255.255.255.255 20002" FAILS to register on Wireshark on 192.168.100.3

It seems like I need to do something additional to get multicast working across subnets.
What am I missing?

Thanks!

[egc]

You need something like smcroute, but I do not know if Entware has it

[puterboy2]

Thanks. I installed 'smcroute' from Entware.

I configured /etc/smcroute.conf as:

[egc]

I think there is a thread in the forum about it you need a lot of iptables to make traffic possible

[puterboy2]

Note, there was a typo above in my invocation of 'smcrouted', the flag should be '-f' and not 'e'.
However, when I checked my conf file with the '-F' flag, I got the following error message:

[puterboy2]

So I tried to see what happens when I broadcast within vs. cross-subnets:

The following broadcasts work within my primary 192.168.1.x net (and are detected by wireshark)
- echo hello | nc -u -b 255.255.255.255
- echo hello | nc -u -b 192.168.1.255
As does the following unicast
- echo hello | nc -u 192.168.1.3 (where 192.168.1.3 is the IP address of the computer I am monitoring with wireshark)

In contrast, when sending from 192.168.1.x to the 192.168.100.x subnet:
The following cross-subnet unicast works when run from the 192.168.1.x net
- echo hello | nc -u 192.168.100.100 (assuming the monitored computer has IP address 192.168.100.3)
But the following cross-subnet broadcasts all fail from the 192.168.1.x net when monitored on the 192.168.100.x subnet
- echo hello | nc -u -b 255.255.255.255
- echo hello | nc -u -b 192.168.100.255

I tried adding the following iptables rules, but they didn't help

[egc]

You must setup smcroute see:
https://github.com/troglobit/smcroute
https://an0n-r0.medium.com/making-dlna-through-site-to-site-vpn-work-f393629f4ce0

I moved this thread to the Advanced networking forum.

I just added smcroute to my build, will have a look at it after the holidays

[egc]

I am adding smcroute to my build and got an error about missing kernel modules.

This is for Kernel 4.4.

Not sure if these are automatically added when you use the entware smcroute but I doubt it.

Set the logging to high and send to syslog to see what is going on, you might even set log level to debug:

[Per Yngve Berg]

Broadcast is Layer 2 (Mac Layer) and will not traverse to other sub-nets because they are not on the same Ethernet.

Can't DLNA use mDNS Multicast for Discovery?

[egc]

[puterboy2]

[puterboy2]

OK, I finally go it to work by compiling and installing `udp-broadcast-relay` (https://github.com/nomeata/udp-broadcast-relay) on my dd-wrt router.
I then ran: