I met the phenomenon is: the server and the client are trying, in some segment of the client can run normally, but some of the network segment will prompt lose connection with the server, but other web applications such as browser, remote desktop is normal, I use the communications protocol is a UDP

I test the network methods and results:
Server: nc - ul 161
Client: nc - uv 192.168. 7.0.x.x -p 161
The result is: the client input text, the server can receive, but the client at the beginning of the prompt "XXXX reverse connection failure", then "SNMP open
"Is a closed network because it is over, I can't go to the inside of the need to find people to help test, is not very convenient, so the test done very rough, don't know on the server the client can receive input characters, also did not test the 161 changed to other port

Question:
I guess program is no problem, the problem was out on the network environment, I need to find and confirmed that network communication is abnormal, the idea right? The network will have this kind of phenomenon, is the normal TCP, udp is normal also, that in some segment other segment is not normal,
You need to use the same command, try the client whether any news from your server, there will be different?
Test port no 161 to switch to other ports, there will be any difference between, can I use programs are using port, or test the other did not use udp port?

CodePudding user response:

What is the meaning of "reverse connection", has been found that the problem? If my guess is that nc test udp, imitate the TCP three-way handshake, sent a few messages to each other, and the client received feedback from the server, so prompt "reverse connection"?