WAN can be problematic yeah.... For some trouble, you can increase the amount of time in the ICMP settings of your discovery wizard.  That helps in some of the cases. But for SNMP alerts, as they are UDP, they aren't guaranteed or suggested over a WAN type connection.  That's one of the reasons we added the health state change alert in the prefs.  For folks that cannot or won't use SNMP, they at least have this health state change alert to tell them their device is degraded. Thx Rob
MD Storage alerts in OME