Observed high mobile data usage after upgrading RUT955 firmware (RUT9_R_00.07.06.16). The complete data allocation for the month was used up in a few short days. There were no devices on the network using this high amount of data. After purchasing another lot of data the same problem occurred again within a short time.
Today I applied the Port 53 rule to the traffic rules of the Firewall which seems to have address the issue (i.e. preventing Port 53 DNS DOS attacks etc.).
This may be helpful to others. See thread below . . .
No it wasn’t. However, I immediately saw a drop in the traffic after implementing the rule. Unfortunately, there still seems to be an issue after there was a failover to the Mobile WAN later on. I had to disable the Mobile Connection again even after the failover and the system returned to the wired WAN. Seems I need to investigate the matter further as it is not fully resolved.
Unfortunately, yes. I have disabled the Mobile WAN until I get some more time to investigate it in more detail. When I blocked port 53 I observed an immediate improvement. However, after the next failover to the Mobile WAN the data usage continued to be high even after it was switched back to standby. This only started happening since my last firmware update. I suspect, but haven’t gotten to investigate fully, that the device is probably switching to a type of load sharing rather than operating in fully a failover mode after a failover incident.