1. A method for processing email for a multi-tenant database system comprising a plurality of data centers and a plurality of instances of a multi-tenant database system core, each of the plurality of data centers implementing at least one of the plurality of instances of the multi-tenant database core, the method comprising: maintaining, at each of the plurality of data centers, an instantiation of a private domain name service (DNS) database, the private DNS database comprising a respective DNS entry for every possible combination of one of the plurality of data centers and one of the instances of the multi-tenant database system core; receiving an incoming email at a first local mail transfer agent (MTA) of a first data center of the plurality of data centers, the incoming email directed to an incoming email address comprising a first domain string that includes a pod token; redirecting the incoming email to a redirected email address comprising a second domain string that includes the pod token and a data center token that identifies the first data center; obtaining, from the instantiation of the private DNS database maintained at the first data center, a destination location for the redirected email address, wherein the destination location is obtained from the respective DNS entry that includes a combination of the pod token and the data center token; and routing the incoming email to the destination location.