Question about application groups

[adelatorre]

When creating an application group, what is the role "Mail Server" used for? Is it for any server in an exchange infrastructure, or does it only apply to servers hosting mailbox databases?

I notice when I go to do a AIR Exchange restore, that it populates the CAS server field with my mailbox server. Is that because I need to specify that the CAS server is a "Mail Server"? (I currently have no Role selected for my cas server)

Thanks.

[Gostev]

I believe, this is for any mail server with SMTP service, since this is what will be checked by the default verification script in case you select this role. Thanks!