A connection from enp1s0 through gateway 192.0.2.1 to TCP port 443 on 198.51.100.20 fails.
Do not change settings; narrow the cause from lower layers upward.
Which sequence is appropriate?
Check link, local address, route, nearby gateway, and finally the remote service. This narrows the failing boundary without changing configuration.
Detailed explanation
Incorrect. It starts with a remote test and then destroys configuration.
Incorrect. It starts with a remote test and then destroys configuration.
Correct. It progresses from link and local network through routing and gateway to the service.
Correct. It progresses from link and local network through routing and gateway to the service.
Incorrect. These checks are mostly unrelated to an IP connection failure.
Incorrect. These checks are mostly unrelated to an IP connection failure.
Incorrect. It changes settings and takes the interface down before establishing the current state.
Incorrect. It changes settings and takes the interface down before establishing the current state.
Try it yourself
An example you can run in a temporary verification environment.
printf '%s
' 'link -> address -> route -> gateway -> remote TCP port'Expected result
link -> address -> route -> gateway -> remote TCP portKey points
- Observe before changing
- Start at lower layers
- Test the remote port last
Notes
- Environment: 診断順序の表示のみ
- Command output formatting can vary slightly by distribution or tool version.
- Run the example in a temporary directory or process when possible.
Foundation review
Read the scope first
Check whether the command acts on the current shell, a new process, an existing process, or a file.
Verify the observable result
Use the supplied command and compare the output with the expected result.