使用JMeter 3.2实现Telnet连接及响应解析可行性咨询

Hey there! Let's tackle your JMeter 3.2 Telnet-related questions one by one:

Absolutely, and you might not even need plugins for your core requirement of checking if a connection can be established (matching telnet open [IP] [PORT]):

• Core JMeter (no plugins) works for basic connection checks: The built-in TCP Sampler can handle this, since Telnet is fundamentally a TCP-based protocol. Here's how to set it up:
  1. Add a TCP Sampler to your test plan.
  2. Fill in the Server Name or IP and Port with your target values.
  3. For pure connection validation (no command sending), leave Text to send empty, or send a simple newline (\n) if the server expects an initial prompt.
  4. JMeter will mark the sampler as successful if the connection is established; it'll throw an error if the connection is refused, times out, or fails for any reason.
• Plugins for full Telnet interaction: If you need to go beyond just connection checks (e.g., send commands, parse interactive responses), you can use the Telnet Sampler from the JMeter Plugins Manager. This plugin handles Telnet-specific protocol details that the raw TCP Sampler doesn't, making it easier for full session simulations.

The key differences come down to protocol handling and use case fit:

• Protocol layer behavior:
  • TCP Sampler operates at the raw TCP level. It sends/receives raw byte data without any built-in awareness of Telnet-specific control codes (like terminal negotiation sequences, echo suppression, or escape characters). It's essentially a generic TCP client.
  • Native Telnet (or the Telnet Sampler plugin) understands Telnet protocol semantics. It automatically handles the WILL/WONT/DO/DONT negotiation steps that most Telnet servers use to configure terminal settings, mimicking a real Telnet client's behavior.
• Use case alignment:
  • Use the TCP Sampler if you only need to validate connectivity to a port, or send raw data to a TCP service (not strictly Telnet). It's lightweight and avoids overhead from Telnet-specific logic.
  • Use Telnet-specific tools/plugins if you need to interact with a Telnet server as a user would—like logging in, running commands, and responding to prompts. The Telnet Sampler will handle protocol nuances that could cause a raw TCP connection to fail or return unexpected data.
• Response parsing:
  • With the TCP Sampler, you'll get the raw response including any Telnet control characters. You can still parse this with JMeter post-processors (like Regular Expression Extractor), but you'll need to account for those extra control bytes.
  • The Telnet Sampler strips out Telnet control codes by default, giving you clean, human-readable output. This makes parsing interactive session responses much simpler.

内容的提问来源于stack exchange，提问作者eeadev