Not sure if the l2tp/vti modification merits inclusion - that depends on personal configuration of which tunnel is inside the other. I think the original config is correct for the more common use case of having l2tp secured by ipsec.
Mar 28 2019
That worked, thanks. Had to set it to 901, the vpn node was 900. Added a sed to the preconfig script so it survives updates.
Mar 27 2019
I switched to a L2TPv3 tunnel for better performance than OpenVPN, still will not come up at boot if it depends on the vti interface.
Mar 26 2019
Probably not the most common config, but I already have IPSec tunnels between all my sites, but need the L2 bridge and ovpn's fragmentation for my TV STB to function correctly through a tunnel. Perhaps adding a depends-on-interface option to all interfaces would be the most generic way to resolve this. I will try and see how difficult this is to implement in the config scripts when I have some time in the next week or 2.
Oct 7 2018
I also have ipsec/vti.
I rechecked the solarflare card - issue still exists. Didn't catch it last time because my config got a little messed up with all the image swapping.
Oct 3 2018
Finally got back up here to test. Swapped out the Mellanox NIC with a Solarflare card on latest, works. 201807292210 image with Mellanox card, works. Latest image and different Mellanox card, broken. Definitely looks like a driver issue, the new kernel seems to have a far older version. No virtualization involved.
Sep 19 2018
I've tried the oldest build, but it still has the issue. Is there any way to extract an image from another router? The timing does line up for it being a driver issue, I'm going to see if swapping to a different NIC helps next time I drive over, debugging remotely atm, so no rebooting allowed for a few days.
Does anyone know where I can find a build on the old kernel? I deleted mine swapping images at some point. Starting to think that might be when it started.
It's what Windows does when you first assign an IP address - checks if it's in use and refuses to use it if it is. Linux boxes don't so they have working IPv4.
IPv6 is all on different subnets, and I actually have working IPv6 networking while IPv4 is broken. v6 uses NDP instead of ARP so shouldn't be able to cause this.
Sep 18 2018
Config's pretty huge, here's the LAN interface. Need to go through and sanitize the rest. No proxy arp or similar anywhere, "arp" doesn't appear in the config at all. Issue occurs on all vlans.
Sep 9 2018
Do you have a copy of 1.2.0-rolling+201808230337 to share? I'd like to get wireguard working, but need L2TP working as well. It's no longer on the download page.
Sep 8 2018
Aug 7 2018
Aug 2 2018
Looks like it was merged, closing, thanks :)
Jul 30 2018
Jul 28 2018
Jul 27 2018
As far as I could tell before, it was triggered by my unique attempt to bridge a vlan to openvpn.
Finally had some down time I could to use to debug this, but it appears to be fixed in the latest revisions. Going back to 201806151501 still breaks it though.
Jun 20 2018
Little more testing..
relevant parts below. The interfaces seem to be added to the bridge, but the bridge interface is not assigned an ip address.