You need to download Management Information Base (MIB) files, after enabling Simple Network Management Protocol (SNMP) for ProxySG or Advanced Secure Gateway (ASG).
Note: To enable MIB, go to Configuration > Services > Management Services.
To download SNMP MIB files for ProxySG/ASG, log in to MySymantec, and go to Downloads > Software Downloads. Within the ProxySG/ASG area of the Downloads section, select your model, and then select the appropriate GA release to locate the corresponding MIB files.
MIB files are only included with General Availability (GA) releases; they are not included in Patch releases.