This article provides the steps to configure the speed and duplex parameters in an Ethernet interface of Kerio Control. This article serves as a guide when troubleshooting issues related to slowness in the network, high CPU usage caused by overruns and underruns, etc.
Typically, the port's speed and duplex parameters of Ethernet interfaces are negotiated and set automatically between hardware devices. However, some hardware devices do not auto-detect speed and duplex settings, and instead, use hardcoded and user-defined values. In this case, Kerio Control fails when it attempts to auto-detect the speed of the connected devices. This results in packet loss and reduced interface speed.
It is crucial to find the correct speed and duplex mode for the device, and configure these values in Kerio Control, to optimize the internet connection.
Changing the speed and duplex settings must be done separately for each interface. To set the correct speed and duplex values:
Go to the Interfaces section in Kerio Control's administration interface.
Right-click on the interface you want to configure (i.e, Trusted/Local Interfaces)
On the context menu, choose Configure port:
On the Configure Port window, select the speed and duplex settings you see fit in the Speed and duplex drop-down menu:
Note: For Kerio Control Software Appliance, some values may not be supported.
Click Apply. Once saved, changes will take effect.
In the case of network connectivity issues, it's recommended to switch from Auto-negotiation mode to another value on the Speed and Duplex dropdown menu. You need to confirm the exact value with your Internet Service Provider (ISP).
On rare occasions, when your provider’s router and the Kerio interface are both on auto-negotiation speed, the packets might not agree (negotiate) with each other and might be jammed.
For advanced verbose output, you might enable the following debug logs:
- Unhandled Ethernet protocols
- Dial on demand
- Low-level driver messages
- Internet connectivity
After the changes have been saved, the internet connection speed and duplex mode should be the same as on the hardware device.