When a job is delegated from Central Administration Server to Managed Media Server the Network Interface option is not available in Job Properties.
Please note that this is by design as the Central Administration Server (CAS) delegate jobs to a MMS (Managed Media server) and since these delegated job's have to use the "Network Interface" setting specified on the MMS, this option cannot be changed on the CAS.
If the jobs running on CAS and is not delegated to any MMS then its network interface settings can be changed through Tools > Options > Network and Security.
This issue is currently being considered by Symantec Corporation to be addressed in the next major revision of the product. There are no plans to address this issue by way of a patch or hotfix in the current or previous versions of the software at the present time. Please note that Symantec Corporation reserves the right to remove any fix from the targeted release if it does not pass quality assurance tests or introduces new risks to overall code stability. Symantec's plans are subject to change and any action taken by you based on the above information or your reliance upon the above information is made at your own risk.
Please be sure to refer back to this document periodically as any changes to the status of the issue will be reflected here.
Please contact your Symantec Sales representative or the Symantec Sales group for upgrade information including upgrade eligibility to the release containing the resolution for this issue. For information on how to contact Symantec Sales, please see http://www.symantec.com
CASO Network Interface Options