smtp-mappable-ips verifiedcriticalWritten by the Hub
Addresses that map intake to sending
in the configuration this is a line
smtp-mappable-ips: 0.0.0.1/0Ranges of local addresses for which mail submitted on an address is also sent from that address.
Values
- Values
addresses and ranges- Default
0.0.0.1/0 · 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
This is the quiet mechanism behind the most useful property of MailerQ's intake: a mailer chooses its sending address simply by connecting to it. Verified one message at a time on the stand — submitted on .86, .83 and .74, each left from the same address. The shipped value covers everything (0.0.0.1/0), with loopback and private ranges taken back out by smtp-unmappable-ips. The mapping is not absolute, though: setting smtp-default-ips replaces it entirely, which is documented nowhere and was found by experiment.
What happens if you get it wrong
An address is submitted on but is outside these ranges.The mapping does not apply. With smtp-default-ips empty the mail still left from that address on our stand, so the fallback is not what the name suggests — see the open question.verified by experiment