| 摘要 |
A method for operating a firewall includes: in response to the firewall receiving a TCP SYN request packet that is sent towards a first node from a second node, said TCP SYN request packet comprising a sequence value ("seq"), sending to the second node a SYN|ACK packet, said SYN|ACK packet comprising a seq and an ack_sequence value ("ack_seq"), where ack_seq of the SYN|ACK packet is not equal to the TCP SYN request packet's seq+1; and in response to the firewall receiving a TCP RST packet from the second node, verifying that the seq in the TCP RST packet matches the ack_seq of the SYN|ACK packet and, if it does, designating the connection with the second node as an authorized connection.
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