Broadcast UDP across VLANS

I have a NMEA gateway as a WiFi client on my Peplink Transit Cat 18. It is broadcasting on UDP 2000. The WiFi network that it is connected to can see the UDP messages. The other VLANs with their own SSIDs cannot. How do I let devices across all the VLANs see the UDP messages. I have tried to implement an internal firewall rule allowing any ip source to see the ip of the gateway but this does not work. Thanks in advance.

Do you have inter vlan routing disabled currently on any of the vlans in question?

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Yes. Vlan routing is on. I can receive NMEA data across all VLANs through TCP but not UDP.

OK great so if TCP is passing then routing between the VLANs is fine.

When you say broadcasting do you literally mean sending traffic to the VLANs broadcast address (ie multicast so sending to on a 192.168.0/24 subnet) or do you mean that to connect to it a device connects as a client to it on UDP port 2000?

Multicast traffic will not cross between VLANs, but there is no reason why you shouldn’t be able to get a client to connect to the NEMA gateway’s IP address over UDP from a different VLAN.

Suggest you set up two specific firewall rules one for TCP 2000 and the other for UDP 2000. Set both to log, source IP of a laptop on the other VLAN, destination your NEMA gateway IP. They try and access it and check to see if the event log lights up saying traffic allowed.


The client (Navionics) only listens out on UDP 2000. There is no option to input an IP address. I guess that is multicast over VLAN and is not possible?