On 5/7/25 07:08, Sean McBride wrote:

Hi all,

I'm migrating a server with older postfix & older mailman2 and noticed one setting in postfix's main.cf:

owner_request_special = no

The postfix docs for this setting say:

"Enable special treatment for owner-listname entries in the aliases(5) file, and don't split owner-listname and listname-request address localparts when the recipient_delimiter is set to "-". This feature is useful for mailing lists."

Which I don't really grok.  I'm not sure why it's set to no on the older server.

It's set to no because yes is the default and the appropriate setting for MM 2.1 is no except it shouldn't matter because owner-listname is not a MM 2.1 address and while listname-request is, in a MM 2.1 installation recipient_delimiter is normally set to +.

-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan

Sean McBride writes:

I'm migrating a server with older postfix & older mailman2 and noticed one setting in postfix's main.cf:

owner_request_special = no

I'm not sure why it's set to no on the older server.

If 'recipient_delimiter' is set to '+', which is the modern convention, this setting is a no-op, because no splitting on '-' would be done anyway. Check the setting with "postconf recipient_delimiter".

Otherwise, to Mailman it still doesn't matter what that setting is, and it's highly unlikely it would matter to other mailboxes served by that Postfix instance.

tldr:

The 'owner-LIST' convention hasn't been used by any mailing list manager in decades as far as I know. I believe it never was used by GNU Mailman. For valid addresses, specifically 'LIST-request', any other splitting that results in 'LIST' wouldn't matter, as Postfix does not change either the metadata (envelope recipient) or the message header, and Postfix delivers to the same pipe to the 'mailman' program -- mailman handles it the same as if Postfix delivered it to the full address. So for a site where all lists are managed by GNU Mailman, the setting doesn't really matter to Mailman.

I'm not sure why Postfix says is it useful for lists. The way Postfix handles splitting (delivering to the full address if valid, otherwise trying the stem after splitting), a properly configured mailing list gets no benefit because all its addresses have explicit aliases. I guess it protects a mailbox for 'owner' from getting bombarded by mail for 'owner-LIST', and lists that don't support 'LIST-request' from being spammed by mail for that address. And in the ancient past when mailing lists weren't served by list management software, but were implemented as manually maintained aliases, I suppose subscribers of accidentally misconfigured lists were protected.

-- GNU Mailman consultant (installation, migration, customization) Sirius Open Source https://www.siriusopensource.com/ Software systems consulting in Europe, North America, and Japan