How to configure SPAN on a Nexus 55xx

I’ve recently needed to configure SPAN a couple times in the lab at work to troubleshoot somespan issues – or at least to see what I could see.  It wasn’t exactly glamorous work, but somebody had to do it.  Now, I had to look it up the first time because it had probably been a good year since I’d done it.  The document I used is here.  Well, the second time I needed to configure SPAN was shortly after the first.  I was annoyed that I had to look at the same document and skip over all the paragraphs to get to the commands, then sort out the FC ports and other commands I didn’t need.  So for my benefit, and perhaps yours, here’s my short and sweet version of how to configure SPAN on a Nexus 5k.

Create SPAN session
switch# conf t
switch(config)# monitor session 1

Configure destination port 
(destination cannot be a FEX port or a port-channel!)
switch# conf t
switch(config)# interface ethernet 1/15
switch(config-if)# switchport monitor
switch(config-if)# exit
switch(config)# monitor session 1
switch(config-monitor)# destination interface ethernet 1/15

Configure source port (or VLAN)
switch(config-monitor)# source interface ethernet 101/1/10
switch(config-monitor)# source interface ethernet 101/1/31


switch(config-monitor)# source vlan 215

Activate a SPAN session
switch(config)# no monitor session 1 shut

Display SPAN session
switch# show monitor


switch# show monitor session 1

And a cut-and-paste version for those who like quickies.

conf t
monitor session 1
int eth 1/15
switchport monitor
monitor session 1
destination int eth 1/15
source int eth 101/1/10
source int eth 101/1/31
no monitor session 1 shut



4 Comments on “How to configure SPAN on a Nexus 55xx”

  1. Ming says:

    nice one! just want to point out the following:

    switch(config)# interface ethernet 101/1/20
    switch(config-if)# switchport monitor

    don’t think FEX host post can be destination port though?

  2. basha says:

    It is wrongly configured
    it is etherenet 1/15

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