You may need to edit client IP address ranges that you want to be authenticated.
To edit client IP address ranges on the list of addresses that require authentication
In Symantec Endpoint Protection Manager, click Admin.
Select and expand the group of Enforcers.
Select the group of Enforcers for which you want to edit client IP address ranges on the list of addresses that require authentication.
Under Tasks, click Edit Group Properties.
In the Gateway Settings dialog box, on the Auth Range tab, in the Client IP address range area, click anywhere in the column of IP addresses and click Edit all.
In the Gateway Settings dialog box, click OK.