| 摘要 |
Disclosed is an FTP application layer packet filtering method comprising the following steps: when establishing a file transfer protocol (FTP) control channel transmission control protocol (TCP) connection, obtaining a first transmission control protocol synchronous (TCP SYN) packet sent by a client and forwarding same to an FTP server; detecting whether the FTP server response packet is a synchronize-acknowledgment (SYN-ACK) TCP packet and, if not, discarding same; detecting whether the client response packet is an ACK TCP packet and, if not, discarding same; establishing a data flow table in order to record and update FTP status. Additionally provided is an FTP application layer packet filtering device. The above method and device are capable of avoiding and protecting against FTP application layer attacks and ensuring the secure, reliable transmission of FTP operations. |
