Hi!

You are less likely to encounter security issues when connecting your ASP.NET apps to the database under UltiDev Cassini, because it runs under powerful Local System (NT AUTHORITY\SYSTEM) account. On the flip side, exposing Cassini applications to Internet is more dangerous compared to IIS running under Network Service account because if the application under Local System is hacked the attacker will be able to do a lot of damage to the system.

To address your issue you may consider using SQL authentication instead of integrated auth, or alternatively, you may create a domain user account (with access rights similar to Network Service) specifically for your application, and grant proper DB access rights in SQL Server. Integrated auth can get tricky when SQL DB and the application are either on different domains or in the workgroup instead of domain. In that case SQL auth would be easier to implement.

Best regards,
UltiDev Team.