Relayed Bounces

Should any of your messages bounce, ReachMail will attempt to relay them to you at one of the following addresses. Only one address is selected for bounce transmission. In the following order: 

1. Return-Path (all connection types)
2. SMTP MAIL FROM (only applies to SMTP connections)
3. From Field (only applies to API connection)

Return-Path

Senders may supply a Return-Path header for both SMTP and API (HTTP) connections. ReachMail will transpose this to the X-RETURN-PATH header in the outbound message and will inject a ReachMail Return-Path address. This enables us to process bounces and ARF messages automatically. 

SMTP MAIL FROM

Only applies to clients connecting over SMTP. This represents the from parameter to the mail command in the SMTP conversation. E.G.

MAIL FROM:<user@email.com>

Often, this is the same address as the Return-Path.

From Field

Only applies to API submissions. If no Return Path is present in the payload, bounces will be relayed to the From field supplied for the message.

Delivery Retry Period

ReachMail will attempt to deliver bounces to one of the aforementioned addresses for 48 hours. Failed attempts bounces cannot be resent after this period nor can they be retried if ReachMail delivery attempt is bounced though users can still retrieve their logs from the User Interface or using the API Reporting endpoints.

Unrouteable Addresses

ReachMail may skip over addresses that appear to be unreoutable over the general internet such as:

root@localhost, joe@joes-macbook, jane@192.168.1.1

This is most common with the SMTP MAIL FROM setting and users encountering this issue should set an alternative Return Path on their messages to ensure consistent relaying of bounces.