# YAMN Nym ingress

This service receives an envelope over the Nym mixnet and delivers the
already encrypted YAMN packet to an allowlisted SMTP entry through Tor.

Transient Tor connection failures are retried three times with bounded
backoff before the SMTP transaction begins. Errors after SMTP commands start
are not retried automatically because the remote acceptance state may be
ambiguous.

The Nym address is generated by the persistent client identity and printed at
startup. It must be copied to `YAMN_NYM_RECIPIENT` on the sending web service.

Required environment:

- `YAMN_ALLOWED_ENTRY_ADDRESSES`: comma-separated exact YAMN entry addresses.
- `YAMN_NYM_INGRESS_STORAGE`: persistent directory for the Nym identity.

Optional environment:

- `YAMN_TOR_SOCKS`, default `127.0.0.1:9050`.
- `YAMN_INGRESS_FROM`, default `<>`.
- `YAMN_DRY_RUN`, default false. When enabled, valid envelopes are accepted but
  not delivered to SMTP, for non-delivery integration tests.

Input protocol, sent as the Nym message body:

```json
{"version":1,"entry_address":"yamn@example.org","payload":"<base64 raw SMTP envelope>"}
```

The service does not log payloads, sender identities, or recipient message
contents. It has no reply, fetch, view, inbox, or fallback-direct-SMTP mode.

An example systemd unit and environment file are in `deploy/`. The production
environment file must be reviewed against the current YAMN remailer list and
must not be committed if it contains deployment-specific secrets.