# Take one neighbor down

> Disable, enable or reset a single BGP session, e.g. while its router is being worked on.

`ansage peer` acts on one neighbor and leaves the others alone. The neighbor is named by its ID
(the first column of `ansage show summary`), its address, or `address:port`.

```sh
ansage peer 10.0.0.1 disable --reason "r1 maintenance, ticket 4711"
ansage peer 10.0.0.1 enable
ansage peer 10.0.0.1 reset
```

| Command                   | NOTIFICATION sent                                     | Afterwards                |
| ------------------------- | ----------------------------------------------------- | ------------------------- |
| `disable [--reason TEXT]` | Cease / Administrative Shutdown, with TEXT (RFC 9003) | stays down until `enable` |
| `enable`                  | -                                                     | connects again            |
| `reset`                   | Cease / Administrative Reset                          | reconnects                |

The reason is shown on the router, for example in FRR's `show bgp neighbor` as the shutdown
message, and in ansage's own `ansage show peer`:

```txt
  Last down: 60.0s ago, administrative: cease (6/9) "maintenance"
```

> **6/9 instead of 6/2?:** With Graceful Restart and the N bit (RFC 8538) negotiated, ansage wraps the Cease in a Hard Reset
> (6/9), so the neighbor withdraws our routes at once instead of keeping them as stale.

## Lifetime

A disabled neighbor stays disabled across a [reload](/docs/guides/reload.md) and enabled again by a
restart. `ansage_peer_disabled` is 1 while it is disabled.

## Disable vs. drain vs. remove

| Goal                                                 | Use                                                                        |
| ---------------------------------------------------- | -------------------------------------------------------------------------- |
| Move traffic off this whole server, sessions stay up | [`ansage drain`](/docs/guides/drain.md)                                       |
| Close one session for a while                        | `ansage peer N disable`                                                    |
| Get rid of a neighbor                                | delete its `[[neighbor]]` and `ansage reload` (Cease / Peer De-configured) |
| Re-establish a stuck session                         | `ansage peer N reset`                                                      |