determine packet headers for a probe packet comprising an inner User Datagram Protocol (UDP) packet encapsulated within an outer IP packet, wherein packet headers for the outer IP packet include a source identifying an address of an agent sending the probe packet, a destination identifying an address of a target network device in a network to be monitored, and a Time to Live (TTL) field having an initialized value of 1, and wherein the packet headers for the inner UDP packet include a source and destination each identifying the address of the agent, a TTL field having an initialized value of 1, and an identifier field having a value identifying the inner UDP packet as a probe;

repeatedly transmit, to the network, the probe packet;

receive responses to the probe packet from network devices in the network, wherein the probe packet is retransmitted at least once by the agent with an incremented TTL value for the inner UDP packet or outer IP packet based on whether a corresponding response to a last transmission of the probe packet relates to the inner UDP packet, wherein the TTL value for the inner UDP packet or outer IP packet is incremented independently each time the probe packet is retransmitted through the network to reach different parts of the network, wherein the TTL value of the outer IP packet is incremented while maintaining the TTL value of the inner UDP packet responsive to receiving a response relating to the outer IP packet and the TTL value of the inner UDP packet is incremented while maintaining the TTL value of the outer IP packet responsive to receiving a response relating to the inner UDP packet;

determine network metrics for the network based on a payload of the received responses; and

output an indication of the determined network metrics.