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Show traffic in a GRE Tunnel


Hello !

I have a N3K-C3048TP-1GE running NXOS 9.3(7) and I am trying to monitor my network interfaces with Zabbix. Everything works fine for the ethernet interfaces but the GRE interfaces do not show up.

I went to CLI and when I display an ethernet interface, the traffic is visible ( but not on a GRE interface (

If anyone has a solution that allows me to know the traffic passing through my different GREs, I'm interested!

Thanks to you.

2 Replies 2

Rising star
Rising star

Hello @kiwiterra 

To monitor the traffic passing through GRE interfaces, you can try using NetFlow to export traffic statistics to a monitoring system such as Zabbix.

Here's an example of how to configure NetFlow on your N3K switch:

-- Enable NetFlow on the switch:

N3K(config)# feature netflow

-- Configure the NetFlow export parameters, such as the IP address of the NetFlow collector, the NetFlow version, and the export interface:

N3K(config)# flow exporter my-exporter
N3K(config-flow-exporter)# destination

N3K(config-flow-exporter)# source <export-interface>
N3K(config-flow-exporter)# version 9
N3K(config-flow-exporter)# transport udp 9996
N3K(config-flow-exporter)# exit

-- Define the NetFlow record to include the traffic fields you want to monitor, such as source and destination IP addresses, protocol, and port numbers:

N3K(config)# flow record my-record
N3K(config-flow-record)# match ipv4 source address
N3K(config-flow-record)# match ipv4 destination address
N3K(config-flow-record)# match transport source-port
N3K(config-flow-record)# match transport destination-port
N3K(config-flow-record)# collect counter bytes
N3K(config-flow-record)# collect counter packets
N3K(config-flow-record)# exit

-- Apply the NetFlow configuration to the GRE interface:

N3K(config)# interface tunnel1
N3K(config-if)# ip flow ingress
N3K(config-if)# exit

-- Verify that NetFlow is working correctly by checking the NetFlow statistics and reviewing the collected data. You can use the [show flow exporter statistics] and [show flow monitor] commands to view the NetFlow statistics.

Once you have configured NetFlow on your N3K switch, you can configure Zabbix to receive and process the NetFlow data, and then use Zabbix to monitor the traffic passing through your GRE interfaces.



Best regards
******* If This Helps, Please Rate *******

he mention CLI 
in NSK if you show interface you can see Rx and Tx count increase but for GRE tunnel this no happened.

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