In Parallels H-Sphere it is possible to allow third-level domain hosters to create e-mail resources under their service domains. I.e., users that host third-level domains
user.domain.com under service DNS zone
domain.com, will be able to create mailboxes like
email@example.com from their user CP.
To allow third-level hosters to create mailboxes under a service domain:
Then, if you search by domain name in the Search menu, affected third-level domains will have the domain type Third level domain (Mail Under Host Domain).