I've just bought a DrayTek Vigor2620Ln (ADSL/VDSL router/firewall with backup WAN port and 4G LTE modem built in - UK version)
I want to be able to create a site-to-site (or LAN to LAN in DrayTek's terminology) VPN via an IPSec tunnel to a Netgear ProSafe firewall I have running at another site. Simultaneously I want to be able to access a L2TP VPN Server running on Windows 2012 RRAS (behind the DrayTek at primary site), via passthrough when I'm out and about.
Having created the site-to-site VPN with a few issues along the way, I have got it working. I have also got the L2TP VPN passthrough working so I can connect from my Windows laptop when away from the main network. HOWEVER, it seems impossible to get both working at the same time. For the site-to-site to work, I have to tick the 'Enable IPSec VPN Service' under the Remote Access Control settings on the Draytek. But once I do this, passthrough of the L2TP Windows VPN fails. If I untick, it is the other way around with the Site-to-site failing and the L2TP passthrough working.
I suspect someone out there will confirm DrayTek routers simply cannot both have a site to site and L2TP passthrough connection connected simultaneously (I momentarily achieved it once, on initial bootup). I appreciate both VPN types use IPSec, however every single Netgear and Linksys router I've owned and used to date has been able to do both simultaneously with zero problems. I'm hopeful I'm missing something, but fear I'm not and the DrayTek will be going back (a shame, as I really like it otherwise!)
Any thoughts appreciated, cheers :-)