Should it be possible to connect to SharePoint services from an external domain generally, or is a network likely to be configured to prevent this?If it should be possible, do you need to configure SharePoint to accept calls to the services from an external domain? (either specifically, or external in general)Thanks

Hi, Did you mean If SharePoint site is in b.com domain; you want to connect the SharePoint site by the user from a.com domain.If the above is your case, I think it’s possible. Of course you need to set up the trust connection between b.com and a.com. Hope this helps Thanks!Stanfford

you can access sharepoint services from any external source as long as you configure it with your current domain also both need to know about each other in order to be accessed. So you need to provide the external source in general with the information of your sharepoint services which you are trying to connect. hope this helps