On 6/14/2012 8:38 PM, Adam Bradley wrote: > I have a situation where email delivered to a single namespace needs > to be delivered to a user who could be in one of a number of > downstream system (but we don't know which one
that sounds... broken. > I was wondering if > I could use "Callback Verification" > http://en.wikipedia.org/wiki/Callback_verification to achieve this? No. Although postfix has address verification, there is no mechanism to try N servers until success, nor a method to store which server accepted the recipient. > > Ideally, I'd like to avoid the use of a look up table. Why? A lookup table is exactly what you need. > > To recap, the mail flow would be as follows > > (In the case where the user exists, send to the appropriate MTA) > -> u...@mail.org <mailto:u...@mail.org> => Callback Verification on > recipient -> MTA hosting 1.mail.org <http://1.mail.org> (miss, user > does not exist in this namespace) > > -> MTA hosting 2.mail.org <http://2.mail.org> (hit! deliver to > u...@2.mail.org <mailto:u...@2.mail.org>) Sorry, but this sounds to me like an accident waiting to happen. I would /strongly/ recommend getting a proper recipient list and populating transport_maps with a user->host mapping. -- Noel Jones
