UDP Broadcast Relay for DNS and SNMP for InterVLAN Printer-Discovery

[LKaderavek]

Before I ask my question I will try to get you familiar with the configuration.

OPNsense with 4 IF.
1x WAN1
1x WAN2
1x LAN
1x WiFi

On WiFi there are 4 VLANs configured, VLAN100, VLAN101, VLAN200, VLAN300.

I need to find printers from WiFi devices in VLAN100, VLAN101 which are installed in LAN.
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In LAN there's a Windows Server 2012 R2 as Print-Server installed, printers are shared.
If I connect over SMB from the desired VLANs to the print-server I can install printers, print from them, I even get the status data.

But...If I want to discover the printers, which are all installed in LAN (range from .31-.51) I can't get the dns and snmp broadcast over VLAN through opnsense to LAN.

I tried many firewall-ruling, non worked out.
I tried Port-NAT, not working.

I found an UDP relay script from a guy on net, which I can't use, because I can't install required FreeBSD packages to device.

So please tell me, is there a way to get this done??

Thanks.

Lukas