Here are the details:
io error: unknown host specified
. SQL Developer can successfully connect and query database if i use the TNS protocol. This is obviously quite frustrating for it to work one way and not the other. I followed all the normal instructions for using the instant client, the directory with instantclient has been addded to the PATH, a TNS_ADMIN entry has also been created, with the directory to the tnsnames.ora file
Well, on a whim, I went to changing everything in my setup to match an windows 2003 server that i had setup with instant client before. The main changes were putting the instant client in a folder at the root of the drive (not program files/oracle/etc), but c:/oracle, i know ive seen other posts saying that oracle was particular about characters in the directory path, maybe spaces are a no-no too?
I also add a bunch more environmental variables, anythign that was on the other machine, ORACLE_HOME (to root of instance), SQL_PATH (same), and added the root of the directory to the PATH system variable, not just the folder with the instantclient files. Anyways, I'm happy its working, anyone one of these changes could have been it though-