Disclosed are a network monitoring device, a method, apparatus and system for resetting a password of the network monitoring device, and a server. The method for resetting the password of the network monitoring device includes: a first characteristic code is generated according to encrypted content; the first characteristic code is sent to a server; a password resetting command from the server and a reset password from a client are received, wherein the password resetting command is obtained by encrypting the first characteristic code with adoption of a first key, and returned by the server after receiving the first characteristic code; and the password resetting command is decrypted by adopting a second key, and the password of the network monitoring device is reset by utilizing the reset password, wherein the first key and the second key are a pair of keys in an asymmetric encryption algorithm.