The third server-side part of docs/spec/features/relay.md ("Live mode",
"Handing held mail down", "Ingest with session context"):
- The link service asks for Inbound push as well as Relay, so the relay
is live while a node is linked (RL-12). It claims up to eight
messages at a time with a 300 s lease (RL-15), downloads each on its
own connection, and unseals it with the downstream's sealing key
(RL-21).
- smtp::inbound::relayed plays the relay's session through this
server's own handlers: connect (rate limits, scripts, milters),
EHLO, MAIL FROM, each RCPT TO, then DATA, on port 25 with the
original sender's address, port and HELO (RL-23). SPF, reverse IP,
DMARC, DNSBL, the spam filter, the AI classifier, Sieve and the
directory see the real facts. The relay's TLS shows in the Received
header and in is_tls, and a new expression variable, relay, is the
relay's name (id 92, in the connect, EHLO, MAIL FROM and RCPT
contexts, with its schema label).
- Live: this server's reply is the verdict. Accepted, the message is
destroyed on the relay and the sender hears 250; refused, the relay
gives the sender this server's reply.
- Held: spam over the reject threshold goes to Junk with
X-Inbuxa-Relay: held, over reject threshold, never refused or
dropped (RL-17). Recipients refused for good get a DSN only when the
sender passed SPF or DMARC here (RL-18); a refusal for now is tried
again after the lease.
- Every message taken is recorded before the relay is told, and one
offered again is destroyed without a second delivery (RL-16). The
records are forgotten after heldMaxAge and a day, and with the relay.
- On the relay, a message waiting for its verdict stays pending when
claimed, so the downstream knows to answer it (spec table updated).
- The spec records the external-directory decision: such domains list
only the accounts already seen, with no catch-all.
- The link system test now sends mail through the real inbuxa-relay:
live delivery before 250, a live refusal (too many Received headers)
that reaches the sender as 450 4.4.6 with nothing kept, and a message
held while the link was off, delivered once when it came back.
jcoffey-dev