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[ScreenOS] How to view and interpret the hardware interface counters (get counter statistics) in WebUI



Article ID: KB4257 KB Last Updated: 01 Feb 2021Version: 16.0

This article details the steps to view and interpret the hardware interface reports/counters in ScreenOS WebUI.



The Interface Statistics report displays hardware counters to help monitor the Juniper firewall device. The hardware counters provide information about hardware performance.

To view and interpret hardware reports, perform the following steps using the WebUI or CLI:


  1. Open the WebUI. For more information about accessing the WebUI, go to KB4060 - Accessing Your NetScreen, SSG, or ISG Firewall Using the WebUI.

  2. From the ScreenOS options menu, click Reports, select Counters, and then click Hardware.

This is an example of the Hardware Counters for Interface ethernet 1.

Image of note

The hardware counters provide the following information. 

These explanations can also be viewed by clicking the Help '?' icon in the upper right corner of the WebUI.

drop vlan Number of packets dropped because of missing VLAN tags, an undefined sub-interface, or because VLAN trunking was not enabled when the security device was in Transparent mode
early frame Number of counters used in an Ethernet driver buffer descriptor management
in align err Number of incoming packets with an alignment error in the bit stream
in bytes Number of bytes received
in coll err Number of incoming collision packets
in crc err Number of incoming packets with a cyclic redundancy check (CRC) error
in dma err Number of incoming packets with a Direct Memory Access (DMA) error
in misc err Number of incoming packets with a miscellaneous error.  Incoming packets with miscellaneous errors that could be related to the IPC open queue, to the hardware queue, or to other hardware failure, such as duplex/speed mismatch.
in no buffer Number of unreceived packets because of unavailable buffers
in overrun Number of received overrun packets.  This counter is used when too many packets hit the interface for it to process at that time. Packets are dropped.
in packets Number of packets received
in short frame Number of incoming packets with an Ethernet frame shorter than 64 bytes (including the frame checksum)
out underrun Number of transmitted underrun packets.  The device generated a transmit underrun error while attempting to DMA (Direct Memory Access) and transmit a packet. This happens if the host is not able to DMA the packet data into the NIC''s FIFO fast enough. Interface has a TX buffer for outgoing traffic, when the rate of traffic pushed to this buffer (could  be DMA or CPU) is too high the interface cannot handle the amount of traffic.  Interface starts to drop packets when the TX buffer is full and thus increments the underrun counter. This can be a sign that the interfaces are running at an inferior speed and/or duplex, or there is too much outgoing traffic that goes through the interface than the buffer can handle.
late frame Number of counters used in an Ethernet driver buffer descriptor management
out bs pak Number of packets held in back store while searching for an unknown MAC address
When the security device forwards a packet, it first checks if the destination MAC address is in the ARP table. If it cannot find the destination MAC in the ARP table, the security device sends an ARP request to the network. If the security device receives another packet with the same destination MAC address before it receives a reply to the first ARP request, it increases the out bs pak counter by one.
out bytes Number of bytes sent
out coll err Number of outgoing collision packets
out cs lost Number of dropped outgoing packets because the Carrier Sense Multiple Access/Collision Detect
(CSMA/CD) protocol lost the signal
out defer Number of deferred outgoing packets
out discard Number of discarded outgoing packets
out heartbeat Number of outgoing heartbeat packets
out misc err Number of outgoing packets with a miscellaneous error
out no buffer Number of unsent packets because of unavailable buffers
out packets Number of packets sent re xmt limit
xmt limit Number of dropped packets when the retransmission limit was exceeded while an interface was operating at half-duplex


  1. From the CLI, enter the command get counter stat to display the interface statistics for ALL the interfaces. 

Enter the command get counter stat interface <interface_name> to display the hardware counters for a specific interface.

The CLI commands will show both flow and hardware counter information.

Image of note

The hardware counters provide information on the general firewall behavior, and the flow counters provide information on the number of packets inspected at the flow level. For more information on the flow counters, see  KB4261 - Viewing Flow counters.

For additional descriptions of the interface counters, refer to the Tables of Screen, Hardware, and Flow Counters in the Concepts & Examples ScreenOS Reference Guide - Volume 3 - Administration:

  1. Go to the ScreenOS Documentation link.

  2. Click your Release version.

  3. Click the Concepts & Examples Reference Guide: Volume 3, Administration.

The tables can be found in the "Viewing Screen Counters" section of the "Monitoring Security Devices" chapter.


Modification History:

2021-02-01: Article reviewed for accuracy and validity; article found valid and useful


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