About certificate requirements for NetBackup 8.1
Starting with NetBackup 8.1, Veritas requires all communications among 8.1 systems be secure. A certificate is required for communication among 8.1 systems. By default, insecure communication with back-level media servers, Auto Image Replication master servers, and clients is enabled. Once all computers in your environment are upgraded to 8.1, Veritas suggests you disable further insecure communication. See the section on enabling insecure communication in the Veritas NetBackup Security and Encryption Guide.