Before you actually read this post on how to create trust. I will recommend you to go through the following post:
1. Basics of Trust: http://www.adshotgyan.com/2010/11/trust.html
2. Types of authentication in Trust: http://www.adshotgyan.com/2010/11/domain-wide-authentication-selective.html
Prior of creating a Trust, it is very important to make sure that we have proper name resolution between the domain/forest
Name resolution can be achieved by the following in DNS:
1. Secondary Zones
2. Stub Zones
3. Delegation
4. Forwarders
5. Conditional Forwarding
Trust can be created by the following ways:
1. Active Directory Domains and Trusts
2. Netdom
If we select the option "This Domain Only", then we have to run the same wizard from the other domain as well. This option is chosen if we do not have the credentials of the other domain. Once we choose the option "This Domain Only" then the administrator of the other domain has to run the same wizard in his domain
The wizard asked you for the credentials of the other domain because we selected the option "Both This Domain and The Specified Domain"
A prompt displaying a message that by default SID Filtering is Enabled on External Trust
To know more about SID Filtering, please read the following post:
http://www.adshotgyan.com/2010/12/sid-history-sid-filtering.html
