Some embodiments provide a method for a first host machine that hosts a virtual machine connected to a particular logical network. The method receives a command to test connectivity between the first host machine and a set of at least one additional host machine that also host virtual machines on the particular logical network. At the first host machine, the method generates a packet for sending to the set of additional host machines in order to test the connectivity. The method appends to the generated packet (i) information that identifies the particular logical network and (ii) a flag indicating that the packet is for connectivity testing. The method encapsulates the generated packet with tunnel endpoint addresses, including a tunnel endpoint located at the first host machine. The method sends the encapsulated packet from the first host machine to the set of additional host machines according to the tunnel encapsulation.