To check the functionality of a content Delivery Network in which the contents made available by at least a Content Provider are made available to a plurality of surrogate sites (POP1, POP2, POP3, . . . ) in the aforesaid contents are included fictitious contents (φ, φ(i), φn) which are selectively recognizable but inaccessible to users and Content. Providers. The functionality of the network is checked verifying the availability of the aforesaid fictitious contents (φ, φ(i), φn) at the surrogate sites (POP1, POP2, POP3, . . . ). The aforesaid fictitious contents are marked with information pertaining to time (TTL), and localization. It is thus possible to verify the updating of the contents made available at the various surrogate sites (POP1, POP2, POP3, . . . ) as well as the proper operation of the network from the geographic point of view, also in regards to the delivery of the contents in conditions of minimum service time.