Question : Setting up a domain trust for to seperate forest

I currently have three locations I am dealing with.  I have location 1 and 2 that are in the same forest.  Location 1 is the main domain with location 2 apart of the same domain.  Location 1 has a domain trust set up with location 3 which is a totally seperate forest.  I can share files to and from location 1 from both location 2 and 3.  However, Location 3 cannot see location 2 and location 2 cannot see location 3.  I can't ping from either 2 or 3.  Location 2 and 1 are in the same domain just for example abc.com.  How can I get def.com to talk to location 2?

Answer : Setting up a domain trust for to seperate forest

location 2 and 3 need to be able to communicate, that is your problem it seems, if they cannot communicate there is not much you can do with the trust/shared recources etc.