MA-net listener does not respect selected interface

[GralfR]

problem:

The DMXrouter lists more MA-devices than available on the network.

situation:

• I have a netowrk with several VLANs and a lot of MA2 and MA3 devices in several VLANs. The network is working, because MA devices find other MA devices that are on the same VLAN only. A MA3 on one VLAN for example does not see any other MA3 devices on other VLANs.
• A Windows 10 PC is connected to this network via a trunk port.
• On that Windows 10 all existing VLANs are created on the driver basis, i.e. by the VLAN-tool of the manufacturer of the NIC. No Hyper-V is installed. So, each VLAN has its own virtual NIC on this system.
• All but one virtual NIC are disabled. So, the only NICs available for software are the trunk and one MA-VLAN (which got a static IPv4).
• Any MA onPC software running on this PC behaves like any other MA device in the network: the onPC does see only the MA-devices inside the selected VLAN, not other devices from other VLANs.
• On this PC DMXrouter 1.11.2 is started and the interface for the MA VLAN is selected.
• The MA-net listener finds MA-devices on the network.

issue:

The MAnet listener does find all MA devices on all VLANs, even on those VLANs that are disabled on this Windows!

guess:

The MAnet listener seams to not respect the selected interface (the virtual NIC for a VLAN). Instead it seams to listen to all interfaces (0.0.0.0 ?), which includes the trunk port of the system, which carries all VLANs and thus receiving all MA-data from all VLANs of the network. BUT: even this trunk does not mix those VLANs together. All VLAN-traffic is tagged inside this trunk. So, the MAnet listener seams to even not respect the VLAN-tags when scanning the network.

request:

The MAnet listener should respect the selected interface and only scan on this interface.
If scanning over several interfaces or receiving tagged pakets, the MAnet listener should group the devices depending on the interface/IP-network/VLAN.

[fiverecords]

Thanks for the excellent report — the level of detail (driver-based VLANs, trunk port, no Hyper-V, the onPC comparison) made this straightforward to diagnose.

Your guess is essentially correct, with one nuance. The MA-Net listener does bind to all interfaces and joins the multicast groups on every NIC, with no per-datagram interface handling. The nuance: it isn't that the listener ignores VLAN tags — on driver-based VLAN setups, all virtual NICs share a single physical multicast filter, and the trunk adapter delivers frames from every VLAN with the tag already stripped before any application can see them. So even scoping the multicast joins wouldn't fix this; the only robust lever from userspace is handling each datagram by its arrival interface.

The wide listening is actually deliberate (discovery is meant to surface consoles on any segment without pre-configuration), but your setup shows that on a trunk port "wide" degrades into an undifferentiated mix of all VLANs. Both of your requests are implemented for the next release:

• A new "Via" column in the MA-Net table shows which local interface(s) each device's presence packets arrived on — always on. In your setup, devices on your MA VLAN will show the VLAN NIC (and possibly also the trunk), while devices from other VLANs will show only the trunk adapter, making the leak immediately visible.
• A new "Only enabled interfaces" option (off by default, persisted) restricts MA-Net discovery to the interfaces enabled in DMXRouter — the same per-datagram isolation policy sACN and PSN reception already use.

One honest limitation: traffic from different VLANs arriving tag-stripped through the trunk all shows the same "via trunk" attribution, since the tags are gone before they reach us — the IP column still separates them by subnet.

I'll update this issue when the release containing the fix is out.

[GralfR]

Thanks @fiverecords for the quick response. Perfect service!

With more columns in the MAnet sheet, I wonder if it's worth having a filter for the view. Maybe You get inspired by the way MA3 offers filters for each column in the headline of each table?

[fiverecords]

I went ahead and implemented it for the next release, in a slightly different shape than per-column filters:

• Click-to-sort on every column of the MA-Net table. IP and "Last seen" sort by their real values, not alphabetically.
• Right-click on the header to show/hide columns and to reset to defaults — the same controls DMXRouter's RDM device tree already offers.
• Column order is drag-reorderable, and the whole layout (including your chosen sort) persists across restarts.

Between sorting on the Via column and hiding what you don't need, this should cover the filtering use case for a discovery-sized table. If these tables ever grow to the point where true per-column text filters earn their keep, that's still on the table as a follow-up.