The services availed from entiies/ persons outside Inida MAYBE liable. This depends on the Place of Provision of Services Rules.
It is important to note that all services are not based on recepient basis. Some exceptions are as under: ( Even if SP is outside India)
1. Event based services maybe - place of event if in India.
2. Property based services - place of immovable property if based in India.
3. Transportation services - detination if India. ( exemption upto cusotms station available)
4. Intermediary service - place of intermediary.
5. Multi locational Service provision- the place in India ( even if small part in India).
Some others - see good commentary on ST or POPS.
If the service from outside India is taxable on RCM then if used for provding taxable services then cenvat credit is eligible.