A method comprising: detecting a first path between a user equipment and a first network entity; detecting a second path between the user equipment and a second network entity, wherein the first path is longer than the second path; and determining whether the second network entity is a proxy server located between the user equipment and the first network entity based on an estimated value of the first path and an estimated value of the second path, characterized in that the estimated value of the first path and the estimated value of the second path are time-to-live values, and the method further comprises: estimating at least the value of the first path, wherein the value of the first path comprises an initial time-to-live value of a response packet from the first network entity, by adding a time-to-live value of the first network entity and a hop count value of the first network entity, and subtracting the added values by one; and estimating at least the value of the second path, wherein the value of the second path comprises an initial time-to-live value of a response packet from the second network entity, by adding a time-to-live value of the second network entity and a hop count value of the second network entity, and subtracting the added values by one. detecting a first path between a user equipment and a first network entity; detecting a second path between the user equipment and a second network entity, wherein the first path is longer than the second path; and determining whether the second network entity is a proxy server located between the user equipment and the first network entity based on an estimated value of the first path and an estimated value of the second path, characterized in that the estimated value of the first path and the estimated value of the second path are time-to-live values, and the method further comprises: estimating at least the value of the first path, wherein the value of the first path comprises an initial time-to-live value of a response packet from the first network entity, by adding a time-to-live value of the first network entity and a hop count value of the first network entity, and subtracting the added values by one; and estimating at least the value of the second path, wherein the value of the second path comprises an initial time-to-live value of a response packet from the second network entity, by adding a time-to-live value of the second network entity and a hop count value of the second network entity, and subtracting the added values by one. estimating at least the value of the first path, wherein the value of the first path comprises an initial time-to-live value of a response packet from the first network entity, by adding a time-to-live value of the first network entity and a hop count value of the first network entity, and subtracting the added values by one; and estimating at least the value of the second path, wherein the value of the second path comprises an initial time-to-live value of a response packet from the second network entity, by adding a time-to-live value of the second network entity and a hop count value of the second network entity, and subtracting the added values by one.