As an organization grows, additional SIMS servers may be added, and users may be migrated from an old server to a new server. As users are migrated, it would be nice if they could maintain the same server domain address rather than have to adopt a new domain address.
In FIGURE A-4 the top drawing shows the company's original email configuration. Users connect to a server called quackadero and access mail using the domain name quackadero.com. In the bottom drawing, quackadero has been converted from a regular mail server to a message access proxy/message access server, and a new server called quasi has been added with a number users having been migrated to quasi. However, even though these users are now on quasi, they can still access their mail using the same quackadero.com domain name. quackadero provides service for users whose account it supports and forwards mail store requests for users supported by quasi.