According to an example aspect of the present invention, there is provided an apparatus comprising at least one memory and the computer program code being configured to, with the at least one processing core, cause the apparatus at least to offer a network-based service, determine whether the apparatus is reachable from a public network, responsive to determining the apparatus is not reachable from the public network, establish a tunnel connection with a relay server, and participate in a cryptographic handshake with a network node, wherein packets comprised in the handshake are communicated via the tunnel connection