HOW TO: Integrate Custom web portal(ASPX) with CRM2015 ON-PREMISE Environment

Steps to Integrate Custom webportal on CRM2015 Default Port

1. Create a Folder(Example: CustomImport) in CRMWeb Folder(Example: C:\Program Files\Microsoft Dynamics CRM\CRMWeb) and Copy/Paste all your files/website in it.
2. Goto CRM Installation Path: CRMWeb\Help\bin (Example: C:\Program Files\Microsoft Dynamics CRM\CRMWeb\Help\bin) and copy all these files and paste it into the above website bin folder (where your Microsoft.Xrm.Sdk.dll located)
3. Goto IIS drill down to the CRM Website and select the Folder which you have created in the Step1.
4. Right Click on the Folder and click Convert to Application
5. Verify Windows Authentication is enabled

If you notice any issues with custom webpage while accessing on HTTPS, perform below steps:

• Run CRMAppPool under a Service Account which you are Impersonating the Custom WebPortal.
• Ensure above Service Account is part of PrivUserGroup {GUID}. 

Note:  It is not a supported solution; However, it works like a charm and it doesn't impact any OOB solution.

Limitations of Dynamics CRM Database when Replicaiton(Transactional) is Enabled

1. Cannot Import Solution/Unable to make any customization changes

• Includes Workflows/Plugin, etc
• CRM Report changes

2. Cannot Import Data using Out of Box Data Import (mass data updates)

Note: Typically it gives SQL Server Error and you will not find any errors on CRM web server most of the time while performing above action.