If your websites or networks are hosted by a third party, then permission from that provider will be required prior to testing. The requirements for this vary between hosting companies, with some companies allowing testing without approval on certain services, and others needing detailed forms to be filled in in advance. In anticipation of a penetration test, it is advised that the requirements around permissions for any services that are hosted by a third party be checked in advance, as without permission, the penetration could be delayed.