DB Link getting appended with "REGRESS.RDBMS.DEV.US.ORACLE.COM"

Hi Guys
I have got a strange problem in my Database. There is a code which development team had written to create a DB link to other database. But its strange to see that the Link created is appended with this name "REGRESS.RDBMS.DEV.US.ORACLE.COM". For ex: if i create a DB link called tester and when i wuery the DBA_DB_LINKS view its showing as "TESTER.REGRESS.RDBMS.DEV.US.ORACLE.COM". I tried to create the DB Link explicitly too. I am faceing the same problem. do we need to do any configuration changes in my DB. kindly put up your suggestions on this.

Thanks a lot in advance...

so whats the actual problem?

show us output of

show parameter db_domain

The Problem is the developers check the condition in the code with the name they created.ex in if clause they check for Tester but as the name is appended by the above mentioned name the if clause is failing. If this happens in all d DB's den they can concatenate the string but this happens in only one db.