METHOD, DEVICE, AND COMPUTER-READABLE STORAGE MEDIUM FOR APPLICATION-DEPENDENT FILTERING OF FILE TRANSFER PROTOCOL PACKETS

摘要

FIELD: radio engineering, communication.;SUBSTANCE: method comprising: when a transmission control protocol (TCP) connection of a FTP control channel is established, the receipt of a first TCP sync packet sent by the client (TCP SYN) and sending thereof to the FTP server; determining whether the response packet from the FTP server is a synchronization + acknowledgement (SYN+ACK) TCP/ACK packet (SYN+ACK) TCP, and if the response packet from the FTP server is not a TCP packet SYN+ACK, discarding the response packet; determining if the response packet from the FTP server is a TCP packet SYN+ACK, whether the response packet is from the client by the TCP-ACK packet, and in the case, if the response packet from the client is not a TCP packet ACK, discarding the response packet; and if the response packet from the client is a TCP packet ACK, creating a data stream table for recording and updating the FTP state, wherein the method further comprises detecting a connection establishment during a three-step negotiation for the data transmission channel TCP packet, monitoring and detecting a TCP interaction process, recording a TCP state, and discarding a data packet not satisfying the interaction protocol.;EFFECT: increased data processing rate.;9 cl, 9 dwg