You need to set up access policy in Administration control,

IP Address Filtering:

Click one of the following options:

Allow all IP addresses to connect. (default) No filtering on any IP address is performed when an administrator is accessing ACS remotely.

Allow only listed IP addresses to connect. Click to allow remote administration from only those workstations whose IP addresses fall within the range specified in IP Address Ranges. Workstations whose IP addresses are not within the specified range will not be able to access ACS remotely.

Reject connections from listed IP addresses. Click to filter out remote administration from the IP addresses specified in IP Address Ranges. Remote administration from workstations whose IP addresses do not fall within the specified range will be permitted.

Note: IP filtering operates upon the IP address received in the HTTP request from a remote administrator's web browser. If the browser is configured to use an HTTP proxy server or if the browser is run on a workstation behind a network device performing network address translation, IP filtering applies only to the IP address of the HTTP proxy server or the NAT device, respectively.

Regards,

~JG

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