公开(公告)号：US20210105219A1

公开(公告)日：2021-04-08

申请号：US16591189

申请日：2019-10-02

Applicant: Cisco Technology, Inc.

Inventor： Hung Chau ,  Zhijun Liu

IPC: H04L12/801 ,  H04L12/26 ,  H04L12/24

Abstract: In one embodiment, a network security device configured to monitor a communication session between a first device and a second device generates a first empty acknowledgment packet specifying a first sequence number and sends the first empty acknowledgment packet to the first device. The network security device may thereafter determine that a response from the first device has not been received within a threshold amount of time and generate, at least partly in response, a second empty acknowledgment packet specifying a second sequence number. The network security device may send the second empty acknowledgment packet to the first device and receive, from the first device, a third empty acknowledgment packet specifying a third sequence number. The network security device may then store the third sequence number in association with the communication session between the first device and the second device.

公开(公告)号：US10951536B1

公开(公告)日：2021-03-16

申请号：US16591189

申请日：2019-10-02

Applicant: Cisco Technology, Inc.

Inventor： Hung Chau ,  Zhijun Liu

IPC: H04L12/801 ,  H04L12/26 ,  H04L12/24 ,  H04L29/08

Abstract: In one embodiment, a network security device configured to monitor a communication session between a first device and a second device generates a first empty acknowledgment packet specifying a first sequence number and sends the first empty acknowledgment packet to the first device. The network security device may thereafter determine that a response from the first device has not been received within a threshold amount of time and generate, at least partly in response, a second empty acknowledgment packet specifying a second sequence number. The network security device may send the second empty acknowledgment packet to the first device and receive, from the first device, a third empty acknowledgment packet specifying a third sequence number. The network security device may then store the third sequence number in association with the communication session between the first device and the second device.