This could potentially be major security risk for your environment, by allowing direct access to your OpsCenter host from internet.
I would suggest having another authentication application or web portal that could further restric access to your OpsCenter Console like Citrix.
Allowing direct access to your OpsCenter host from the internet could lead to unauthorized access to your NetBackup Environment.
The following HTTP and HTTPS ports are checked for availability in the specified sequence and the first available port combination is used by default:
1: 80 (HTTP) and 443 (HTTPS)
2: 8181 (HTTP) and 8443 (HTTPS)
3: 8282 (HTTP) and 8553 (HTTPS)
Once again: Please Note: Allowing this type of access would not be recommended.