Configure a service for operating a mail server.
The returned service may include POP3 servers, SMTP servers, or both,
depending on the configuration passed in. If there are multiple servers,
they will share all of their non-network state (i.e. the same user accounts
are available on all of them).
| Parameters | config | Configuration options specifying which servers to include in the returned
service and where they should keep mail data. (type: Options) |
| Returns | A service which contains the requested mail servers. (type: IService
provider) |