A zone file used to forward zones often used with Other DNS servers.
Stub zones are similar to forwarding zones because they allow your server to send recursive queries directly to specific DNS servers. However, whereas a forwarding zone is just an entry in a configuration file, a stub zone is an actual zone file. It's named for the fact that it represents a stub of the actual authoritative primary zone located on a different DNS server. A stub zone contains the authoritative zone’s SOA record, NS records, and possibly the glue records. The server hosting the stub zone gets these records from the primary name server holding the authoritative zone. In Address Manager, this zone type is often used with Other DNS servers (external DNS servers), where the Other DNS server represents the authoritative primary.
Note: Address Manager doesn't support Stub Zones stored in Active Directory, so it can't import them or deploy them. However, any stub zones stored in Active Directory aren't affected during deployment.