[Dovecot] Transparent Migration from cyrus to dovecot

[Noel Butler]

On 12/10/2013 19:22, Daniel Parthey wrote:

> No mail will be lost, since it should remain in the remote MTA's mail
> queue for a while in order to be retried and delivered later.
> 

No guarantee there, some services are broken and do not retry, hotmail 
used to, and I've heard in some cases, still does, do this, some 
marketing system (ok, so thats no loss) do this - there reasoning is 
because of such high outbound queues, it would only delay first runs and 
upset their clients, again, no loss to me, but one persons spam can be 
anothers ham.

It is after all why we have secondary MX's, on network, and if need be, 
off network.