Reach external servers with URL under intranet domain
When setting up our windows domain controller we choose a domain mycompany.com for the domain controller's domain. The problem is we have servers OUTSIDE of our intranet that use e.g. server1.mycompany.com as URL. If we configure our Windows clients to use our domain controller as the DNS server, we cannot reach those servers. Even configuring our internet gateway router as the primary DNS server (and the DC as the seondary) we sometimes cannot reach them - probably ur domain controller somehow gets in the way.
What do we need to seamlessly use external and internal servers under the mcompany.com domain?