...
The CLI Vendor Defaults tab (Settings icon > Setup > Credentials > CLI Vendor Defaults tab) lists well-known (and therefore weak) username and password combinations. These credentials are a subset of the published vendor default usernameusernames/passwords used when the device is shipped by the manufacturer.
...
NetMRI will try site-specific usernameusernames/passwords, in priority order, when first logging in to a device via a CLI connection (SSH or telnet). Once NetMRI determines a password, it will save it as information specific to the device. If there is no site-specific password, the The system will try the vendor default credentials in priority order if there is no site-specific password. NetMRI will always use site-specific username/password combinations when trying to determine the new login credentials for a device, and they will not be used for vendor default credential checks.