Trust relationships between domains on Windows

Trust relationships are an administration and communication link between two domains. A trust relationship between two domains enables user accounts and global groups to be used in a domain other than the domain where the accounts are defined.

Account information is shared to validate the rights and permissions of user accounts and global groups residing in the trusted domain without being authenticated. Trust relationships simplify user administration by combining two or more domains into an single administrative unit.

There are two domains in a trust relationship:

  • The trusting domain. This domain trusts another domain to authenticate users for them.
  • The trusted domain. This domain authenticates users on behalf of (in trust for) another domain.

Trust relationships are not transitive. This means that explicit trust relationships need to be established in each direction between domains. For example, the trusting domain may not necessarily be a trusted domain.