Mapping processing details when used in Assistant/Forward or as a List Member

In VPOP3, 'Mappings' let you associate an email address with a user or list. Usually these are used for when messages first arrive into VPOP3 from outside or from a local user.

Mappings take precedence over the default routing to users.

For the sake of this article, let us say that your local domain is 'example.com', and you have users called 'Joe', 'Sarah' and 'Kate' and Mappings of 'joe@example.com' -> 'kate' and 'joseph@example.com' -> 'joe'

In this example:

  • if a message arrives addressed to 'joe@example.com', it will be delivered to 'Kate', because of the first Mapping
  • if a message arrives addressed to 'joseph@example.com', it will be delivered to 'Joe', because of the second Mapping
  • if a message arrives addressed to 'kate@example.com', it will be delivered to 'Kate', because of the default behaviour and no Mapping overrides that.

If you use a Mapping email address in a user's Assistant or Forward To setting or in a distribution or mailing List, then VPOP3 will also try to process the Mapping, and this document explains how that works, and how the behaviour can be modified. Th

Default Behaviour

Historically, VPOP3 would not process Mappings in Assistant or Forward To settings or List Members and instead would only allow you to use local usernames or list names here (or external email addresses), so, for backwards compatibility, this is the priority behaviour by default:

So, in the example situation, if Sarah has an assistant called 'joe@example.com', then when a message arrives for Sarah, it will be delivered to Sarah and Joe, even though there is a Mapping of joe@example.com -> Kate. This is purely because, historically, Mappings weren't checked at all in Assistants.

If Sarah has an assistant called 'joseph@example.com', the message will be copied to Joe, because, in current versions Mappings are checked, if the default routing cannot find any user or list that matches, and as there is not a user called 'joseph', VPOP3 falls back to checking Mappings

In most cases, this behaviour is OK, because it is unusual to have a user's default email address overridden by a Mapping. However, sometimes there is a problem, so VPOP3 allows you to override this behaviour, either globally, or in a particular instance.

Override to Historic Behaviour

It may be that your system is configured expecting the historic behaviour of only checking for users or lists, and not checking Mappings at all. In this case, there are two options:

  • Prefix the Assistant or Forward To or List Member with the '-' character. In this case, VPOP3 will only check for a user or list which matches the address, and it will ignore all Mappings. This override applies just to that particular setting
  • Stop VPOP3, and at the command prompt, run VPOP3Settings set \secret\~legacylistexpansion 1 . Then restart VPOP3. Now, VPOP3 will ignore Mappings when processing all relevant settings. Note that this cannot now be overridden for individual settings.

Override to Checking Mappings First

It may be that you prefer that VPOP3 checks Mappings first, so that they always take precedence. This logically makes more sense than the default behaviour, but it is not backwards compatible, which is why it is not the default behaviour

To achieve this, there are two options:

  • Prefix the Assistant or Forward To or List Member with the '+' character. In this case, VPOP3 will check Mappings first, and then check for a user or list which matches the address if no Mapping exists. This override applies just to that particular setting
  • Stop VPOP3, and at the command prompt, run VPOP3Settings set \secret\~expansionmappingsfirst 1 . Then restart VPOP3. Now, VPOP3 will always check Mappings first when processing all relevant settings. Note that this cannot now be overridden for individual settings.