Demo
Demo

Knowledge base

smarthost verified

Send everything through another server

in the configuration this is a linesmarthost:

Hostname of a server every message is handed to, instead of being delivered to the recipient's own mail server.

Values

Values
hostname or address
Default
· taken from the build
applying
restart required
where it can be set
in the config file · with a startup flag · as an environment variable

In detail

With this set, MailerQ stops being the last hop: it resolves nothing, connects to one place and gives everything to it. That is how a node is chained behind another MTA, placed in front of a tracking service, or made to route through an appliance a customer insists on. It is worth separating from the debugging sink: the smarthost is a routing decision — the message is genuinely delivered onward — while smtp-sink-address redirects the TCP connection while everything else pretends to be normal. Both can be set at once, and then the smarthost decides the logical destination while the sink decides where the connection actually goes. A per-message smarthost property overrides this for individual mail, which is how a rewrite rule can divert one campaign without touching the node.

What happens if you get it wrong

Set on a node whose telemetry is being read.Every delivery result reports the smarthost as the receiving server, so per-domain statistics describe one destination and reveal nothing about actual receivers.inference · inference
The smarthost refuses or is unreachable.All mail fails at once, regardless of destination — a single point of failure by design.inference · inference