This is an original planning guide. It is not a vendor manual, an official standard, or legal advice. Example addresses use documentation ranges. Review every command before you paste it.
What this hour is for
VyOS Troubleshooting Commands is a single symptom and a read command. VyOS uses set, then compare, then commit. A Junos file is not a VyOS file even when the words look close. You do not reconfigure the device to see if the symptom moves.
A confirmed commit is the habit on a remote box, so a lost session can return the previous config. Write the symptom in one sentence before you type: what should work, what you observed, and which interface or policy.
If the read shows a hostname you did not expect, stop. If the same read fails twice, stop. The previous revision is the rollback. A secret does not go into the note.
A packet capture or a mirror is a different page, and only for a port the ticket names. This page does not scan a network and does not open a rule to the world to test a theory.
The change you can finish
Apply nothing during the writing of the note. When the lab window opens, it is one change on the device named in the ticket. Read the draft, then the device, then decide.
Rollback is the file or the revision you saved first. You do not invent a rollback after the only copy is gone.
- Write the symptom and the hostname.
- Confirm you administer the device.
- Save nothing yet unless a change is already planned; do read the current state.
- Run one read that matches the symptom.
- Record the output line that answers the question.
- Stop, or hand a single change to the feature how-to.
Mistakes that outlive the command
VyOS troubleshooting goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.
- Changing the config to test a guess.
- The wrong device.
- Opening a rule to the world as a test.
- A capture of traffic you were not asked to take.
- Several unrelated shows and no sentence.
- A reboot as the first step.
- A secret left in the pasted output.
Decisions to write down
One decision for VyOS troubleshooting: The symptom is one sentence. The hostname matches. The first action is a read. No rule was opened to test. Output with secrets is redacted. A change, if needed, has its own how-to. And you stop after one failed read repeated.
Checks before you call it done
Confirm this before you call the change done: The symptom is written. The hostname matches. One read is in the ticket. No config change was made as a test. Secrets are redacted. And the next step is one change or a stop. If one of those fails, stop.
# Troubleshoot by reading.
# VyOS uses set, then compare, then commit. A Junos file is not a VyOS file even when the words look close.
# Do not open 0.0.0.0/0 to test.
# Redact secrets before the output goes in the ticket.Before you leave the device
VyOS Troubleshooting Commands ends when the hostname on the device matches the hostname in the ticket. If it does not, you are on the wrong box. Stop. A command that succeeded on the wrong box is not progress.
The draft stays a draft until a person has read the names in it. A generator does not log into the device and does not know which interface is the uplink. You delete a line that names a device, a zone, or a prefix you did not write down.
0.0.0.0/0 is not kept because a sample included it. A source you can say is the source you keep. 192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24, and 2001:db8::/32 are documentation. They belong in the note. They are not prefixes you type onto a production device because they appeared in a draft.
prompt-for-this is a reminder that a secret is missing. It is not a password, a key, a community string, or a pre-shared key you save in the ticket or in git. The real secret stays in the store.
One change is the window. A VLAN and a routing protocol and a VPN do not share it. If two things move and the result is wrong, you will not know which one did it. The next feature waits for its own page.
If the same step fails twice, stop for the day. The failure is the result. Adding a forum command beside a half-applied config produces a device nobody can rebuild. Restore the copy you took first.
A second person reads the device name and the change aloud. If they cannot find them in the ticket, the note is not done. Silence is not agreement. Then leave the device alone.
This page is a planning guide. It is not a vendor manual, not an official standard, and not a permission to touch a network you do not administer. The pillar guide owns the wider design. This page owns one lab proof.
Tools for this guide
This guide does not name a browser tool. The pillar it belongs to links the calculators for the neighbouring work.
Related pillar guides
More in this cluster
The pillar for this page, and the next published pages filed with it.