Telnet 命令参考手册

dubbo 3.x在dubbo协议的默认端口（20880）上并不支持ls等多种命令，而是支持log，clear，exit，help,log level，status，trace这几种命令。在Qos端口（22222）上支持ls等多种命令。

Locate the existing Telnet and QoS command documentation in the website and compare its port-specific command lists with the issue. Verify that Dubbo 3.x documents log, clear, exit, help, log level, status, and trace for port 20880, and the broader commands such as ls for port 22222; done means the reference clearly distinguishes the two ports.

Written by the indexing model from the issue text.