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
A VRF is a routing table with a name. VRF-Lite is that idea without a wider MPLS VPN. The planner drafts names. It does not configure a router. Two VRFs that import everything from each other are one table with extra steps.
Write what is allowed to cross. A prefix you do not originate does not get imported because the lab looked empty. Documentation prefixes are the example.
One router you administer. One new VRF. The interface that will join it is a later ticket.
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.
- Name the router.
- Name the VRF.
- Write what may cross, or that nothing crosses.
- Keep foreign prefixes out.
- Do not configure the router.
- Stop.
Mistakes that outlive the command
VRF and VRF-Lite Explained goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.
- Importing every route.
- A VRF on a router you do not administer.
- A foreign prefix added to fill space.
- The interface moved during the reading.
Decisions to write down
One decision for VRF and VRF-Lite Explained: The router is yours. The VRF has one name. Leaking is explicit or forbidden. Nothing was configured. And foreign prefixes are absent.
Checks before you call it done
Confirm this before you call the change done: The router is written. The VRF name is written. The leak rule is one sentence. No interface was moved. And no route was imported. If one of those fails, stop.
Before you leave the device
VRF and VRF-Lite Explained 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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