  Recently [Cavalcanti \textit{et al.} Nat Commun \textbf{6}, 7941 (2015)]
proposed a method to certify the presence of entanglement in asymmetric
networks, where some users do not have control over the measurements they are
performing. Such asymmetry naturally emerges in realistic situtations, such as
in cryptographic protocols over quantum networks. Here we implement such
"semi-device independent" techniques to experimentally witness all types of
entanglement on a three-qubit photonic W state. Furthermore we analise the
amount of genuine randomness that can be certified in this scenario from any
bipartition of the three-qubit W state.
