Which two external authentication servers are supported for administrative access to a Junos device? (Choose two.)

RADIUS (Remote Authentication Dial-In User Service) is a widely supported network protocol that provides centralized AAA management for users connecting to network services, including administrative access to Junos devices.

While LDAP can be used for directory services and sometimes authentication, it is not one of the primary, fully supported external authentication protocols for administrative access on Junos devices in the same direct manner as RADIUS or TACACS+.

ACE (Authentication, Authorization, and Accounting) is a general term or a specific product (e.g., RSA ACE/SecurID), not a standalone protocol like RADIUS or TACACS+ that Junos directly integrates with as a primary external authentication server type.

TACACS+ (Terminal Access Controller Access-Control System Plus) is another robust and widely used AAA protocol, often preferred in enterprise environments for its distinct separation of authentication, authorization, and accounting functions, and is fully supported by Junos.