Knowledge base
smtp-extractcriticalWritten by the HubdirectiveWhether x-mq-* headers in a submitted message are turned into delivery instructions and stripped before sending.rabbitmq-localWritten by the HubdirectiveWhere incoming mail addressed to an address listed as local is published, instead of being sent onward.smarthostdirectiveHostname of a server every message is handed to, instead of being delivered to the recipient's own mail server.smtp-sink-addressdirectiveRedirects the TCP connection of every delivery to one address, while the rest of the engine behaves as though the mail were going to its real destination.envelopedirectiveSets the return address for a message published from the command line.extract-recipientsdirectiveWhen the binary is used as a command-line utility, take the recipients from the message's own headers instead of the command line.smarthost-portdirectivePort used when connecting to the smarthost; falls back to the standard SMTP port.smarthost-usernamedirectiveUsername offered to the smarthost when it requires authentication.smtp-sink-ipdirectiveAccepted by the binary; printed nowhere and absent from the stock config.smtp-sink-passworddirectivePassword offered to the sink.smtp-sink-portdirectivePort used when connecting to the sink; documented as 25 when unset.smtp-sink-usernamedirectiveUsername offered to the sink when it demands authentication.spool-extractdirectiveWhether x-mq-* headers in a spooled file are turned into delivery instructions.Driving a modern MTA from a mailer that only speaks SMTPcriticalWritten by the HubmechanismTwenty-two headers turn an ordinary SMTP submission into a fully specified job, and the engine removes them before the message goes out.The message as the last wordcriticalWritten by the HubmechanismTen of the twenty-four properties override something the node has already decided — so the job is the fourth and final configuration layer.localWritten by the HubqueueWhere mail to addresses listed as local is published instead of being sent onward.Rewrite RulesimportantWritten by the Hubconsole screenProgrammable handling of every job as it leaves the queue — nine condition types, eleven actions.Local email addressesWritten by the Hubconsole screenRoutes incoming mail for matching addresses into a queue of its own instead of the common inbox.rewrite_actionsimportantdatabase tableWhat a rule does: set or remove a sending address or pool, add or remove tags, delay, redirect to a smarthost, patch the job.rewrite_triggersimportantdatabase tableSelects messages to be modified on consumption, with a time window, a precedence and an enabled flag.localsWritten by the Hubdatabase tableIncoming addresses that are not relayed but published to a queue of their own — postmaster, abuse, feedback loops.rewrite_conditionsdatabase tableExtra tests a message must pass — on the envelope, the subject, or any JSON property — before its rule applies.begindatabase fieldWith until, the period during which a rewrite rule applies; zero at both ends means always.incomingWritten by the Hubdatabase fieldThe recipient pattern that makes incoming mail be published to a queue instead of relayed onward.precedencedatabase fieldThe order in which rewrite rules are considered.recipientcriticalWritten by the Hubmessage propertyThe address the message is delivered to — the only strictly required property.smarthostmessage propertyHands this message to a named server instead of the recipient's own.x-mq-smarthost-hostnameemail headerHands this message to the named server instead of the recipient's own.x-mq-smarthost-portemail headerPort used when connecting to the named smarthost.A rewrite rule faileddelivery stateA rewrite rule could not be applied to the message.Read and rewrite the messageplugin functionNine functions that read and replace every part of an incoming message — including the whole job as JSON.Read and classify an addressplugin functionThe address group: read the address as text, ask whether the engine considers it local, and change that answer.