# Sieve filtering and ManageSieve

Bongo stores each user's server-side mail rules independently from the mail
payloads. `bongosieve` provides the ManageSieve management protocol, while
`bongorules` evaluates the active script as mail passes through the Queue.
Thunderbird and other ManageSieve clients can therefore maintain filters
without editing server files.

## Listener and authentication

ManageSieve is disabled by the base template until it is required. Its
suffixless `sieve` document has conservative loopback defaults:

```json
{
  "enabled": false,
  "listen_address": "127.0.0.1",
  "port": 4190,
  "allow_legacy_tls": false,
  "proxy_protocol_enabled": false,
  "proxy_protocol_networks": [],
  "maximum_script_size": 1048576,
  "maximum_connections": 64
}
```

The greeting offers `STARTTLS`; GNU GSASL mechanisms are advertised only
after TLS. Authentication uses the same Bongo user and app-password policy as
the mail protocols, with the Sieve service scope. Cleartext received after a
`STARTTLS` command is discarded before negotiation. PROXY protocol has the
same source-restricted rules as the other mail listeners.

## Management protocol

The RFC 5804 service implements `CAPABILITY`, `STARTTLS`, `AUTHENTICATE`,
`HAVESPACE`, `PUTSCRIPT`, `CHECKSCRIPT`, `LISTSCRIPTS`, `GETSCRIPT`,
`SETACTIVE`, `RENAMESCRIPT`, `DELETESCRIPT`, `NOOP`, and `LOGOUT`. Script
names and literals are bounded, syntax is validated before activation, an
active script cannot be deleted accidentally, and scripts are isolated by
authenticated user.

The implementation advertises `fileinto`, `envelope`, `body`, `variables`,
`vacation`, and `vacation-seconds`. Actions include keep, discard, file into a
folder, redirect, reject, and vacation response. Vacation history is durable
so repeated delivery does not generate an immediate reply loop. Scripts and
vacation state live in `/var/lib/bongo/dbf/sieve.sqlite`; include that database
and its SQLite sidecars in backups.

## Filters in Webmail

The Web filter editor and ManageSieve are two interfaces to the same intended
user rule model. A filter may match senders or other message properties and
deliver matching messages to a folder such as `Family`. Mailing-list
recognition is one possible filter condition, not a separate replacement for
the filter system. Future JMAP support must map to the same rules rather than
creating a third incompatible store.

Test script upload, syntax rejection, activation, rename, retrieval, deletion,
folder delivery, redirect, reject, vacation deduplication, and quota limits
before exposing the service. The 0.7 release cases are SIEVE-01 through
SIEVE-05 in [release-testing-0.7.md](release-testing-0.7.md).