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Promiscuous Switchport Config

We have a group coming in to do some testing and I am tasked with establishing a 3750G switch between 2 3560E switches. The 3750 will trunk the 2 different vlans between the 2 3560s. I must set up a promiscuous port on the 3750 so the team doing the testing can see all traffic going between the switches. I am wondering if I am able to configure 1 access port for the test team to be able to see all traffic between the 2 switches?

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Promiscuous Switchport Config

You can setup a SPAN session.

conf t

monitor session 1 source interface x

monitor session 1 destination interface y

Where x is the trunk and y is the destination interface. It's possible to filter VLANs as well.

Daniel Dib
CCIE #37149

Daniel Dib CCIE #37149 Please rate helpful posts.
New Member

Promiscuous Switchport Config

I am going off the request that is the reason for using the promiscuous. But the SPAN may work, how would the access port be configured to allow the test team to access the traffic once SPAN is configured?

Current 3750  trunk port configs

int gi1/0/23

switchport trunk encap dot1q

switchport trunk allowed vlan x, y

switchport mode trunk

int gi1/0/24

switchport trunk encap dot1q

switchport trunk allowed vlan x, y

switchport mode trunk

Promiscuous Switchport Config

Dan,

Once you put a destination port in, the destination port goes into "monitor" mode. It doesn't need a specific configuration on the port, nor does it matter if it's access or trunk port. Keep in mind that when the destination port is configured as a destination in a span session, you cannot pass traffic from the host connnected to that port any longer unless you use the ingress option.

HTH,
John

*** Please rate all useful posts ***

HTH, John *** Please rate all useful posts ***
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