[systemd-devel] networkd: example of VLANFiltering=1 but with 1 ip on 1 of many vlans?

[Harry G. Coin]

I'm asking for a short example of a few .netdev and .network 
/etc/systemd/network files for something that I thought would be 
straightforward, but I've lost in the transition to using 
VLANFiltering=1.  I've looked for examples in the docs and online, but 
failed to find any guidance.  I've tried some variations but am beaten 
and need a boost.

  I'm using kernel v5.2 on ubuntu's 'testing' / eoan.

Suppose for example simplicity 3 nics, each carrying vlans 100-300 of 
arbitrary traffic sorts across all nics, and also vlan 3 across all 
nics  which has a well known static ipv4 stable gateway and dns.  With 
the bridge netdev using VLANFiltering=1, and say one of the nics uses 
PVID=3 egressuntagged=3, and the host bridge on _just_ vlan 3 needing  
static  ip for simplicity 192.168.50.60/24 but without generating leaks 
onto the other vlans that are almost certainly carrying addresses that 
conflict/overlap.

What are the minimum set of files in /etc/systemd/network necessary to 
get that done?   Try though I did, I can't find a combination of 
settings/files that causes systemd-networkd to both assign the host the 
ip on vlan3. bring it up and send traffic to it.

Thanks in advance!

Harry Coin