Hello!
I have an issue with OSPF toward a third party router and I want to see details of the OSPF packets received and sent over the link. How can I easily get a packet capture from a Cisco nexus switch?
Thanks!
Victor
Good question Victor!
Using the command-line version of Wireshark, called TShark (for Terminal Wireshark), Cisco developed the Cisco NX-OS Ethanalyzer. The TShark is a network protocol analyzer on the CLI.
Besides, it is embedded on NX-OS the Tcpdump feature. It is a NX-OS CLI application that can be used to capture and prints out a description of the contents of packets on a network interface.
An example for tcpdump can be found below:
N9k(config)# feature bash-shell
N9k(config)# exi
N9k# run bash
bash-4.2$ tcpdump --help
bash-4.2$ sudo tcpdump -w file.pcap -i Eth1-1
tcpdump: WARNING: Eth1-1: no IPv4 address assigned
and an example of the ethanalyzer command:
N5k-UP# ethanalyzer local interface mgmt capture-filter "tcp port 23" limit-captured-frames 100 write bootflash:///telnet-capture2
A relevant article is going to be published at Indeni blog with testing at the Indeni lab these embedded to NX-OS packet capture features. Stay tuned.
If you have any issue regarding Router or IP Address Conflict on your router. Then you can visit which makes its way into the system even if the device is in sleep mode.