mqtt connect by domain, while lost dns service messeage

[jokerMeis]

Hi, I have an mqtt client that login to EMQX by token. During the test, the token expiration time was set to 3 minutes. After the token expired, the ack hour was used to determine and the token was updated to log in to EMQX again. However, after several hours, it was found that when the mqtt connection requested domain name interpretation from the DNS server, No more data is returned. After verification, a UDP packet has been sent to the DNS resolution service, but no reply has been received yet. After restarting the software, requests to the DNS resolution service can be initiated again. May I ask what aspects might cause this situation? The solution I came up with is to use dns buffering, but I don't seem to see such a module in mongoose. Could you please tell me how to enable it

[scaprile]

Mongoose does not handle nor cares about nor knows about tokens. MQTT handling is standard. Anything outside of that is your responsibility. The DNS functions do work and should keep working with no expiration nor usage time limits; anything related is a problem on your implementation. DNS requests are performed when you call a function that requires resolving a name, Mongoose is embedded-oriented and does not do buffering.

Please see our documentation, and follow the guidelines in our tutorials.

Please sniff your network (using Wireshark, for example) and observe the traffic.
If, after your network inspection, you find an actual issue, feel free to open an issue, fill the issue template, and provide us with pertinent information (including useful network capture files; no snapshots, please attach capture files) in order to reproduce and fix the issue. We don't inspect your code for errors, please send the minimum piece of code that can reproduce the issue

[jokerMeis]

This is the data packet we captured. After running continuously for a certain period of time, there has been no response to the dns request packet.

This is the packet capture data under normal circumstances.
It is certain that there is no problem with the network and it has always been smooth.

[scaprile]

Please sniff your network (using Wireshark, for example) and observe the traffic. If, after your network inspection, you find an actual issue, feel free to open an issue, fill the issue template, and provide us with pertinent information (including useful network capture files; no snapshots, please attach capture files) in order to reproduce and fix the issue. We don't inspect your code for errors, please send the minimum piece of code that can reproduce the issue

no snapshots, please attach capture files

Nevertheless, I see Mongoose is sending an UDP message in port 53 to the Google DNS and nobody answers. That is your problem, either because of a firewall, a router, your ISP.