Shaping Option Resolution Order and Precedence

When resolving the configuration for a site, the options are resolved in the following order:

1. The values for the default domain block are taken as the base
2. Any matching provider blocks are then merged in
3. Any matching provider + source blocks for the current source are merged in
4. Any matching site name blocks are merged in. These are domain blocks that have the default (implied) or explicitly configured mx_rollup = true option set in them.
5. Any matching domain blocks are merged in. These are domain blocks that have mx_rollup=false set in them.
6. Any matching site name + source blocks are merged.
7. Any matching domain + source blocks are merged.

Within any of these steps above, the options are merged in the order that they appear across your configuration files, so the most recently specified value will take precedence overall.

You can specify replace_base=true in a block to have that block override the current set of accumulated values.

Warning

There is currently no mechanism for unsetting an option previously merged in. If there is a throttle set earlier (for example in [default]) that you wish to unset rather than explicitly define a different throttle then you must use replace_base=true to replace all previously merged options.

Most options merge directly over the top of earlier options, but the additional_connection_limits and additional_message_rate_throttles options merge the maps together.