SOLVED How can I receive UDP multicast packets in an iocage jail?

[whiskeyjack]

I'm running an Domoticz instance in an iocage jail without VNET enabled and I'm trying to get my Xioami sensors to work. They are added fine, but then never updated. This likely is because Domoticz inside the jail is not receiving the broadcast UDP packets. Running tcpdump -i em0 -n port 9898 shows the packets are seen by FreeNAS:

Code:

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on em0, link-type EN10MB (Ethernet), capture size 262144 bytes
17:25:08.598905 IP 192.168.1.80.4321 > 224.0.0.50.9898: UDP, length 135
17:25:18.579668 IP 192.168.1.80.4321 > 224.0.0.50.9898: UDP, length 135
^C
2 packets captured
559 packets received by filter
0 packets dropped by kernel

And the jail (with IP 192.168.1.7) is listening according to netstat -l:

Code:

udp4	   0	  0 192.168.1.7.9898							  *.*

I can't run tcpdump in the jail without VNET enabled, but Domoticz doesn't show any packets received on port 9898.

If I create a jail with VNET support, will I be able to receive broadcast UDP packets inside the jail? I'm a networking noob, so if something else is going on or if I need to configure something else, then please enlighten me :)

 

[m0nkey_]

If I create a jail with VNET support, will I be able to receive broadcast UDP packets inside the jail?

Yes.

 

[whiskeyjack]

Right, thanks for the confirmation. I did read that VNET gives the jail a full network stack, just did not understand if that is required for receiving broadcast packets.

Thanks!

And by the way, this indeed solved my Domoticz problem: Xiaomi sensors are now updating