[Dovecot] IP based virtual users: stripping login domain?

[Alan Ferrency]

Hello.

I have a likely unusual request regarding IP based virtual
dovecot users.

When you specify a passdb passwd-file name containing "%d", then the
domain portion is stripped from the login username, before the user is
checked in the passwd-file. However, if you specify a passwd-file name
containing "%l" (the local IP), the domain portion of the login is not
stripped off before the username is checked in the passwd-file.

This behavior makes sense, and should be considered the right and proper
thing to do. But in this case, I want to do something different anyway.

In the setup I'm working on, most logins will use domain based virtual
usernames. However, if a customer logs in with an unknown domain in
their login username, I'd like to fall back to IP-based virtualization,
based on the local IP they connect to.

I can't use auth_username_format to strip off %d, because that would
break the domain based virtualization. What I need is an option to make
%l work the way %d already works; or a format inside a passwd-file which
allows for partial matches in the "username" column.


If I can do this directly using a passwd-file, I'd like to do that. It
seems like it'd be easy if I were using an SQL back end, but that's not
an option. It's possible with an external authentication script, but I
want to explore more direct configuration options, first.

Does anyone have any recommendations? If what I want can't already be
done, and I patched dovecot to do one of these things, how likely
would it be to have that patch merged into the project?

Thanks,
Alan Ferrency
pair Networks, Inc.
alan at pair.com