I'm developing a new node.js based frontend for an old intranet site using mssql server and Classic ASP. Both the new and the old site will coexist during the transition phase and both must access the same mssql server using the same database principals.

The old ASP/IIS site uses integrated windows login. The new node-based frontend has to use sql server based logins/principals (edit: while the IIS/ASP site must keep using Windows server principals) and all existing database users/principals must keep working wherever they login from.

From reading around, it appears that a database principal can not be assigned to multiple server principals, therefore it seems unlikely there's a simple solution to this.

I'd like to know if anybody has had to deal with a similar situation before and how they've gone about it.