Create a One-Way, Incoming, External Trust for Both Sides of the Trust
Applies To: Windows Server 2008, Windows Server 2008 R2
You can use this procedure to create both sides of a one-way, incoming, external trust. You must have administrative credentials for your domain as well for the reciprocal domain. If you have administrative credentials only for your domain, you can use the procedure Create a One-Way, Incoming, External Trust for One Side of the Trust to create your side of the trust. Then, have the administrator for the reciprocal domain create a one-way, outgoing, external trust from his or her domain.
A one-way, incoming, external trust allows users in your domain (the domain that you are logged on to at the time that you run the New Trust Wizard) to access resources in another Active Directory domain (outside your forest) or in a Windows NT 4.0 domain. For example, if you are the administrator of sales.wingtiptoys.com and users in that domain need to access resources in the marketing.tailspintoys.com domain (which is located in another forest) you can use this procedure to establish a relationship so that users in your domain can access resources in the marketing.tailspintoys.com domain.
You can create this external trust by using the New Trust Wizard in the Active Directory Domains and Trusts snap-in or by using the Netdom command-line tool. For more information about using the Netdom command-line tool to create an external trust, see Netdom Overview (https://go.microsoft.com/fwlink/?LinkId=111537).
Membership in Domain Admins or Enterprise Admins in Active Directory Domain Services (AD DS), or equivalent, is the minimum required to complete this procedure. Review details about using the appropriate accounts and group memberships at Local and Domain Default Groups (https://go.microsoft.com/fwlink/?LinkId=83477).
To create a one-way, incoming, external trust for both sides of the trust
Open Active Directory Domains and Trusts.
In the console tree, right-click the domain for which you want to establish a trust, and then click Properties.
On the Trusts tab, click New Trust, and then click Next.
On the Trust Name page, type the Domain Name System (DNS) name (or NetBIOS name) of the external domain, and then click Next.
On the Trust Type page, click External trust, and then click Next.
On the Direction of Trust page, click One-way: incoming, and then click Next.
For more information about the selections that are available on the Direction of Trust page, see "Direction of Trust" in Appendix: New Trust Wizard Pages.
On the Sides of Trust page, click Both this domain and the specified domain, and then click Next.
For more information about the selections that are available on the Sides of Trust page, see "Sides of Trust" in Appendix: New Trust Wizard Pages.
On the User Name and Password page, type the user name and password for the appropriate administrator in the specified domain.
On the Outgoing Trust Authentication Level--Specified Domain page, do one of the following, and then click Next:
Click Domain-wide authentication.
Click Selective authentication.
On the Trust Selections Complete page, review the results, and then click Next.
On the Trust Creation Complete page, review the results, and then click Next.
On the Confirm Incoming Trust page, do one of the following:
If you do not want to confirm this trust, click No, do not confirm the incoming trust.
If you want to confirm this trust, click Yes, confirm the incoming trust, and then supply the appropriate administrative credentials from the specified domain.
On the Completing the New Trust Wizard page, click Finish.