I like to setup a software VPN Gateway for users to be authenticated by Azure AD.
I come across SoftEther https://www.softether.org/4-docs/1-manual/2._SoftEther_VPN_Essential_Architecture/2.2_User_Authentication
A session mention about "RADIUS Authentication" I am wondering if this will work with Azure AD.
Or else in session: "2.2.4 NT Domain and Active Directory Authentication". I am not sure if the mentioned Active Directory is the same as Azure Active Directory.
The referenced link is talking about the standard Windows Server AD and not Azure AD. Azure AD as a cloud service supports auth using protocols such as OAuth, OpenIDConnect and not the same as AD on prem such as Kerberos, NTLM, LDAP.
I have not tested or can say that it will work but if your Radius server can reach an Azure IaaS network address then you could test using Azure AD Domain Services which adds Kerberos, LDAP for applications that are hosted in or can reach your Azure virtual