Task timeout - 听云Network

Step 1: Obtain the scatter point details link of the error report
Step 2: Open the scatter point details link and obtain the corresponding captured packets

Step 3: Packet capture analysis (the task timeout Error corresponds to the analysis of the packet information (TCP, SSL) corresponding to the timeout stage)
SSL Handshake: Certificate verification, a protocol used to encrypt and secure communications that occur over the Internet.
Common SSL filtering rules:

ssl, tls (filter all data packets related to ssl handshake)

ip.addr==target Hostip address (filtering only contains data packets related to target Hostip)
SSL Handshake Time overview (TLSv1.2):

Client->Server: client_hello

Server->Client: server_hello,

Server->Client: Certificate, Server Key Exchange, Server Hello Done

Client->Server: client_key_exchange, change_cipher_spec, encrypted_handshake_message

Server->Client: New Session Ticket, change_cipher_spec, encrypted_handshake_message
Under normal circumstances, TLS1.2 handshake information is shown in the figure below

First, use the packet capture tool to open the packet capture and enter tcp or ip.223.93.161.60&&tcp in the filter condition (directly inputting tcp is filtering by protocol, but to accurately obtain the packet information we want to analyze, we need to filter accurately and filter according to the monitoring target Hostip). It can be seen that the packet capture is in the SSL Handshake Time stage, and the server sends Server Hello message, the client also sent a confirmation ACK, but the server did not send "Certificate, Server Key Exchange, Server Hello Done" subsequently. After 30 seconds, the client actively sent a FIN message to close the tcp connection.
Step 4: Instant Testing result (reproduction)
Use 8874172Probe to reproduce and find that the Probe is no longer online. In this case, you can use the Probe settingshosts of the same city operator (Beijing Mobile) to map to the 223.93.161.60 target Host to reproduce. The reproduction is normal.

Step 5: Solution

Based on the dimension of packet capture analysis, we can first feedback to the customer to check the status of the corresponding server certificate.

Based on the situation where Probe is not online and the Probe is normal when using the same province (city) operator, we can report that the data transmission Exception may be due to packet loss, which causes the SSL Handshake Time to fail.