I am trying to setup build servers, and a mac available for remote builds in VS. As results I have a Synology server setup with VPN enabled. The Firewall and all settings are setup according to the synology guide. I have then enabled port forwarding on my linksys WRT1900ACS router, for the three ports needed (500,1701,4500), which is also enabled in the firewall on the router. I then access the VPN locally without any issues, tried with different guides (guide1 guide2 guide3).
I then create copies of the vpn connection and inserting my static IP from my ISP. I logon to a tethered internet from my phone, as to ensure the network is different. I then get an error:
local l2tp connection attempt failed because the security layer encountered a processing error during initial negotiations.
Searching it seems like it is an error with the registry (reg 1 reg 2). Changing that just makes the vpn connection hang. What am I doing wrong? After waiting a long period of time (several minutes), the same error returns.
I have also tested on an Ipad using the settings defined in ios-settings.
For others the above guides solves the issue if you have a static IP. You however have to ensure that your ISP, have allowed the traffic, and that your router does not receive a double IP registration, rendering your static IP invalid.
which was the case for me.