I have a persistent problem with Teamwork snapshots:
About 8 out of 10, my VPN tunnel gets dropped when sending an ArchiCAD .pln snapshot, the file size can vary between 150-200MB. Re-trying cost me a lot of time at the end of the day, and we need those snapshots to be safe.
According to all logs, VPN server drops connection because the Mac OS VPN client became unresponsive.
Note: this is not a site-to-site tunnel, it's a tunnel between server and a single Mac.
I can successfully send larger files over the same VPN tunnel without such problems. ArchiCAD sending a snapshot file somehow causes the Mac to stop responding to VPN ping-back during transfer. I've been monitoring my ADSL line as well, and its quality does not seem to be the problem, attenuation is very good, noise margins are stable, there are few errors, etc.
Does anybody have a faintest idea what may be going on?
Possible fix: ArchiCAD has ~30 second timeout (can't say exactly) and if I manage to reconnect the VPN quickly then ArchiCAD will successfully retry. Is there a way to modify that timeout to at least 60 seconds so I have the time to re-open the tunnel? This is far from ideal, but at least it's been tested to work.
Yes, using a Mac. After trying different scenarios (including the ones you proposed) and observing network conditions it became clear that this is some type of protocol implementation problem on either end.
I'd recommend any ArchiCAD user to stay away from L2TP/IPSec.
We switched our entire office over to OpenVPN (using the same appliance) and all the problems disappeared, as I anticipated.
I don't know why Apple does not have a built-in OpenVPN client in 2020, but maybe it's better that way.