I've cento 6.6 client and server in VM network. now i installed oracle database server and client.
after that i lost connectivity to each other(between client and server). i m not getting how to recover.
please help, thanx in advance.

You've been a member here for seven years now...you should be well aware of the Question Guidelines. You have posted no relevant details that would let anyone help you, and you also need to read the LQ Rules about text-speak, and not using it (it's "thanks", not "thanx").

What you've posted gives no one ANY clues/hints that would even let us guess. However, since you've been asking about Oracle for years now:
https://www.linuxquestions.org/quest...-a-4175489032/
https://www.linuxquestions.org/quest...-a-4175495996/
https://www.linuxquestions.org/quest...-linux-827417/
https://www.linuxquestions.org/quest...lation-905211/

...you should have at least some knowledge of how to troubleshoot Oracle client/connectivity issues. Also, you say "client and server in VM network"...what does that mean? Both running on VM? WHICH VM? Do both have network connectivity? And as you've been told before, Oracle is NOT FREE...if you're using it, you need to be paying for it, so you really should just call Oracle support (which is why you pay, among other reasons).

A serious and supportive suggestion to OP:
Web-research the topic of "soft skills".
What would you reply to a friend who said:
? You would ask for additional information,
necessary for any further troubleshooting.

Please learn to do that, to learn to use the WWW on the Internet.
Thank you for your consideration of others.