Provided are techniques and apparatuses for determining the geographic
location of a node on a network. In a representative embodiment, a data
packet is received over the network from a second node, the data packet
including a network identifier for the second node and a Time-To-Live
(TTL) field that has a value, with the value of the TTL field for the
data packet indicating a maximum additional number of hops that could
have been made by the data packet. A probe packet addressed to the
network identifier for the second node is then sent, the probe packet
also including a TTL field. The initial value for the TTL field of the
probe packet is set based on the value for the TTL field of the data
packet.