A computing resource service provider receives a request from a customer to establish a physical connection between a provider network device and a customer network device in a colocation center. Once the connection has been established, the customer may transmit cryptographic authentication information, through the physical connection, to the provider network device. The provider network device transmits this information to an authentication service operated by the computing resource service provider to verify the authenticity of the information. If the information is authentic, the authentication service may re-configure the provider network device to allow the customer to access one or more services provided by the computing resource service provider. The authentication service may transmit cryptographic authentication information to the customer to verify the identity of the computing resource service provider.