Viktor Dukhovni:
> On Fri, Apr 05, 2013 at 09:23:42AM -0400, Wietse Venema wrote:
>
> > Wietse Venema:
> > > I've done a proof-of-concept implementation that works as documented
> > > below the signature.
> >
> > I was able to simplify this further. The result is below.
> > Comments are welcome.
First, lest I sound ungrateful later, thanks for the comments.
> One issue this does not discuss is the handling of:
>
> propagate_unmatched_extensions = canonical, virtual
>
> a relay that accepts multiple extensions and validates addresses
> via relay_recipient_maps, may forward mail via SMTP to downstream
> destinations which handle a subset (possibly none) of the supported
> extensions. This can create bouncebacks.
This problem is old: it exists whether or not recipient_delimiter
specifies a single character or a set of characters.
> postfix-users+extens...@example.com
> user-extension+more-extens...@example.net
This problem is old, too: it exists whether or not recipient_delimiter
specifies a single character or a set of characters.
Note that an address extension exists only because the owner of the
email address decided to use that extension in the first place.
If the owner of an email address decides to use address extensions,
then she should choose a username that doesn't contain any of the
common user/extension delimiters.
Wietse
