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WARNING: This documentation covers Parallels H-Sphere versions up to 3.1. For the latest up-to-date Parallels H-Sphere documentation, please proceed to the
official Parallels site.
When a mail server accepts a message and later decides that it can't deliver the message,
it is required to send back a bounce email to the sender of the original message.
These bounce emails are often misdirected.
This document outlines the correct configuration of mail server where mail bouncing should always work.
Starting with hsphere-mail-service-3-25 (H-Sphere 2.4.3) and hsphere-mail-service-4-14 (H-Sphere 2.5+)
mail servers are by default configured in accordance with this scheme.
Mail bouncing policy implies the following three independent strategies:
See Qmail bounce parameters for details.
1. Separate IP for sending bounced mail
Separate IP for sending bounced mail allows sending bounces, but isolates them to a different IP address
(so that spamcop can block them without blocking other mail).
How to configure:
The respective bounce IP network alias must be up. Then, specify the bounce IP in the
/var/qmail/control/bouncingip file and restart qmail
or set the bouncingip parameter in
the Qmail Settings form in admin CP.
After that, restart qmail.
2. Processing error responses
There are 2 main error status groups:
- temporary errors: delivery of such messages is done during queue lifetime period
- permanent errors: after the first delivery attempt the message is queued as a bounce message
In many cases temporary error status is inadequate. For example, the absence of mailbox or quota overlimit
is sometimes considered by a remote box as a temporary error - as a result,
the message may remain in the queue during lifetime period.
New hsphere-mail-service packages adds a possibility to configure 3 additional states:
- Consider temporary errors as permanent errors for local mail delivery
- Consider temporary errors as permanent errors for remote mail delivery
- Consider temporary errors as permanent errors for local and remote mail delivery
How to configure:
Set the temperror parameter in /var/qmail/control/options:
- temperror=0 or absent (default) - common behavior;
- temperror=1 - consider temporary errors as permanent errors for local mail delivery;
- temperror=2 - consider temporary errors as permanent errors for remote mail delivery;
- temperror=3 - consider temporary errors as permanent errors for local and remote mail delivery.
3. Bounced message delivery
Bounced message delivery is performed in 3 ways:
- simple bouncing: message is bounced;
- double bouncing: message is sent to a predefined location;
- triple bouncing: - message is discarded.
Current mail configuration allows regarding double bounce as triple bounce.
We have added a possibility to configure common bounce delivery as double bouncing or even triple bouncing.
This may be useful when queue grows big and common message delivery suffers.
However, in many cases this configuration is not recommended and should be applied only in critical situations.
How to configure:
et strictbounce parameter in /var/qmail/control/options if necessary:
- strictbounce=1 - consider simple bounce as double bounce
- strictbounce=2 - consider simple bounce and double bounce as triple bounce
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