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Understanding SPAN / Port Mirroring on Cisco Switches

jpaulrhodes5
Level 1
Level 1

Hello Cisco Community!

I've recently began encountering Cisco switches performing SPAN/ Mirroring on ports to make a copy of sets of traffic and exporting them for collection and analysis. While I feel like I understand most of how this process functions, I can not seem to find documentation or forums supporting or denying  if the  device collecting from the SPAN port is able to communicate back to the network it is collecting on. Does a SPAN port block all outbound traffic from the collection device? Does assigning an IP address to the collection device change anything?

 

Thanks you to anyone who is able to help me, first time posting!

1 Accepted Solution

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balaji.bandi
Hall of Fame
Hall of Fame

SPAN Port can not take any action, If you want to take any action the device capturing, then you need to have 2 interfaces to the device, one will capture and other interface connect to the network will have communication to take action?

 

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BB

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2 Replies 2

marce1000
VIP
VIP

 

 - A span destination is a passive dumb-end, it doesn't even block traffic from the span-destination, it just sends span-traffic to it. 

 M.



-- ' 'Good body every evening' ' this sentence was once spotted on a logo at the entrance of a Weight Watchers Club !

balaji.bandi
Hall of Fame
Hall of Fame

SPAN Port can not take any action, If you want to take any action the device capturing, then you need to have 2 interfaces to the device, one will capture and other interface connect to the network will have communication to take action?

 

is this what you looking?

 

BB

***** Rate All Helpful Responses *****

How to Ask The Cisco Community for Help

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