I'm using SoftEther on SBS2011, with L2TP/IPSec protocol.
My initial client is Windows 10 with built-in L2TP/IPSec protocol.
In my SoftEther Users, if I add a wildcard (*) user, and select "NT Domain Authentication", my user is able to connect. Note that on the client, the user is specified without any domain info. SoftEther has a default hub set up, so the username works without specifying hub name.
In this configuration, with a wildcard user, my security log shows…
2018-11-22 15:42:42.059 The connection "CID-65-75130DACDA" (IP address: 79.77.X.X, Host name: 79-77-xxx-x.dynamic.dsl.as9105.com, Port number: 1701, Client name: "L2TP VPN Client - Microsoft", Version: 4.28, Build: 9669) is attempting to connect to the Virtual Hub. The auth type provided is "External server authentication" and the user name is "vluk\spencer.wood".
2018-11-22 15:42:42.059 Connection "CID-65-75130DACDA": Successfully authenticated as user "domain\domainuser".
2018-11-22 15:42:42.059 Connection "CID-65-75130DACDA": The new session "SID-DOMAIN\DOMAINUSER-[L2TP]-12" has been created. (IP address: xx.xx.237.6, Port number: 1701, Physical underlying protocol: "Legacy VPN - L2TP")
2018-11-22 15:42:42.059 Session "SID-DOMAIN\DOMAINUSER-[L2TP]-12": The parameter has been set. Max number of TCP connections: 1, Use of encryption: Yes, Use of compression: No, Use of Half duplex communication: No, Timeout: 20 seconds.
2018-11-22 15:42:42.059 Session "SID-DOMAIN\DOMAINUSER-[L2TP]-12": VPN Client details: (Client product name: "L2TP VPN Client - Microsoft", Client version: 428, Client build number: 9669, Server product name: "SoftEther VPN Server (64 bit)", Server version: 428, Server build number: 9669, Client OS name: "L2TP VPN Client - Microsoft", Client OS version: "-", Client product ID: "-", Client host name: "pcname.hostname", Client IP address: "xx.xx.237.6", Client port number: 1701, Server host name: "192.168.X.X", Server IP address: "192.168.X.X", Server port number: 1701, Proxy host name: "", Proxy IP address: "0.0.0.0", Proxy port number: 0, Virtual Hub name: "VPN", Client unique ID: "04CB9F2131DABA5XXXXF85C77D68E48D")
If I remove the wildcard user and add a specific user called "domainname", the user cannot connect.
2018-11-22 15:43:38.344 The connection "CID-66-5B8386C5FC" (IP address: 79.77.X.X, Host name: 79-77-X-X.dynamic.dsl.as9105.com, Port number: 1701, Client name: "L2TP VPN Client - Microsoft", Version: 4.28, Build: 9669) is attempting to connect to the Virtual Hub. The auth type provided is "External server authentication" and the user name is "domain\domainuser".
2018-11-22 15:43:38.344 Connection "CID-66-5B8386C5FC": User authentication failed. The user name that has been provided was "domain\domainuser".
Does the user need to belong to a specific group on the domain? I wouldn't have thought so, as the same use can cannot when are authenticated with the wildcard user.
What could I possibly be doing wrong?
Best Answer
Earning the "Tumbleweed" badge prompted me to post my own answer (or rather, the non-optimal workaround)
The problem was due to the user trying to connect via VPN was logged into the PC as a non-Administrator user. Once I changed their account to a local administrator, everything worked fine.
I cannot come up with a reasonable explanation for this, particularly why it non-admin users work, as long as they are authenticated by a softEther wildcard user.
If anyone can explain, I'll change the accepted answer.