User Cannot Access Intranet SharePoint Through Non-Domain-Member PC

Issue: User cannot visit intranet SharePoint site through a PC that is not a member of domain, even in the same network (via vpn).

Reason: Website Header does not support fully qualified server name. In my case, our server only support server URL http://intranet but not http://intranet.company.com.

Solution: In IIS Manager, add binding of http://intranet.company.com to intranet web site.