Few weeks back we had some requirement to change our existing version of Oracle Names server running on 8i to upgrade to latest. I thought of going to 10g, but unfortunately for me Oracle discontinue Oracle Names server in this release with LDAP. These I looked for 9i, but for that too I got mixed resonse, whether this version has Names server or not. But I got the answers after some good response in Oracle Forum from experts (Thanks to them). This was the official last release which carries Names Server and along with that it has LDAP too. So I got what I want, but how to do that, I mean how to install that: Here is How:
1. Run the Installaer and choose custom installation, as in standard ones you will not get Names Server.
2. Once the installation is done follow this link to configure it : http://download.oracle.com/docs/cd/B10501_01/network.920/a96580/namingcf.htm#506800
3. Start names server and either you can upload all information about you instances to connect via tnsnames.ora or individually add one entry, by netmgr > choose names server > select Manage data > add > enter details > execute.
4. Once you are done with above, just modify your client sqlnet.ora to use your names server.
5. You can test your entry via namesctl command too like this :
NAMESCTL > QUERY alias a.smd
where alias is the name of the alias being used to connect with from the client application
6. Do a tnsping from client PC too.
Happy Troubleshooting !!!