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
An IPsec failure is often a mismatch: version, proposal, identity, or the prefixes. The compatibility checker and the overhead calculator take values you type. They do not log into a firewall.
Write which phase failed, in the words the log actually used. Do not paste a key from the log into the ticket. Redact it and rotate it if it leaked.
Changing both ends at once means you will not know which edit mattered. Pick the end you administer and change one thing in a later window.
Do not open the proxy identities to the world to force the tunnel up.
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 which peer and which phase.
- Compare the proposal on paper.
- Compare the prefixes.
- Redact any secret in the log.
- Change nothing in this hour.
- Hand one mismatch to a change window.
Mistakes that outlive the command
Troubleshooting IPsec VPN Tunnels goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.
- Both ends edited together.
- A key copied into the ticket.
- Proxy identities opened to the world.
- A new tunnel added beside the broken one.
- Logs ignored.
Decisions to write down
One decision for Troubleshooting IPsec VPN Tunnels: The phase is named. The proposal was compared. The prefixes were compared. Secrets are redacted. And no change was made.
Checks before you call it done
Confirm this before you call the change done: The peer is in the ticket. The mismatch is one sentence or there is no mismatch yet. No key is in the note. No world identity was added. And the next window changes one side. If one of those fails, stop.
Compare first. Change one side later.
Redact keys in the log.Before you leave the device
Troubleshooting IPsec VPN Tunnels 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.
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