Google Apps now has multi-domain support, allowing organizations with two or more domains to manage from a single control panel.
Until now, Google Apps permitted one domain per account. That has become an issue, especially for larger organizations, migrating employees on multiple domains. Companies would either set up other domains as domain aliases or set up different Google Apps accounts for each domain.
According to the blog !escunid , this is how the process worked before:
Source: !escunid Online Business Development
The new multi-domain support is an admin control that allows people on different domains to keep their email addresses but see co-workers from other domains in the organization's global address book.
Multiple domain support is a standard of Microsoft Exchange. Multiple domain support is offered through its online services but there are limits on the number of domains available.
Zoho also supports multiple domains. According to Raju Vegesna:
"A typical business has multiple domains associated (imagine RWW having readwriteweb.com, rww.com, rrweb.com etc). Now you may want to create email addresses, subdomains etc for each of these domains. Supporting multiple domains lets you do things like create aliases that work with all domains. For example, you have firstname.lastname@example.org, but you can easily create aliases so that email@example.com and firstname.lastname@example.org can point to your actual email address.
There are several other advantages with supporting multiple domains. In our case, we have three divisions (Zoho, ManageEngine, WebNMS etc). For each of the divisions, we have separate email addresses with that domain name and then sub-domains, product names etc. Managing all these from a single console is a unified experience. That is how we internally use it. But we have several customers who use it in other ways."
Multiple domain support is available for Google Apps Premiere and Education edition users at no additional charge.