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
BGP chooses a path using attributes you can name. For an enterprise, the first questions are the neighbor address, your ASN if you have one, and the prefixes you originate. You do not announce a prefix you do not hold.
The best-path tool drafts a preference from attributes you type. It does not open a session. A lab session belongs on the vendor page, with a peer named in a ticket.
A default from a provider and a default you generate are easy to confuse. Write which one you mean. A full table is a memory and a filter problem, not a badge.
Nothing on this page is a method for announcing someone else's network. If the prefix is not yours, it is not in the outbound policy.
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 peer and why the session may exist.
- List the prefixes you originate.
- Say whether you accept a default.
- Say whether you accept more than that.
- Keep filters explicit.
- Do not open a session from this page.
Mistakes that outlive the command
BGP Explained for Enterprise Admins goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.
- A prefix you do not originate.
- A session to a stranger.
- A full table accepted with no filter.
- A secret in the note.
- A lab session opened against a provider without a ticket.
Decisions to write down
One decision for BGP Explained for Enterprise Admins: The peer is named. Originated prefixes are yours. Inbound policy is explicit. No session was opened here. And no one else's prefix is advertised.
Checks before you call it done
Confirm this before you call the change done: Peer and ASN are written. Outbound prefixes are listed. Filters are a sentence. No unauthorized announcement is described as a step. And configuration waits for the vendor page. If one of those fails, stop.
Advertise only prefixes you originate.
Do not open a session from this page.Before you leave the device
BGP Explained for Enterprise Admins 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
These tools run in the browser on this site. They do not log into your machines.
Related pillar guides
More in this cluster
The pillar for this page, and the next published pages filed with it.