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November 13th, 2024 20:30

Port Mirroring on Switch Dell EMC N1148T-ON

Hi all,

I am configuring port mirroring for Dell EMC N1148T-ON Switch. Below is the current network model I am using. Currently this Switch is a WAN Switch placed behind Peplink and before the Firewall. This Switch connects to Peplink with 2 uplink ports (port Te1/0/25, Te1/0/26) and is grouped into 1 port-channel (po1). I have configured the monitor session as follows:

Switch(config)# monitor session 1 source interface gi1/0/1
Switch(config)# monitor session 1 source interface gi1/0/2
Switch(config)# monitor session 1 source interface gi1/0/3
Switch(config)# monitor session 1 source interface port-channel 1
Switch(config)# monitor session 1 destination interface gi1/0/31

As the command line above, I have configured the source monitoring interfaces gi1/0/1, gi1/0/2, gi1/0/3 (these are the interfaces connected to the local device), port channel po1 (Te1/0/25 + Te1/0/26) and the output interface connected to the monitoring device is port 13. However, on the monitoring system, I can only see traffic between private IPs (of interfaces gi1/0/1, gi1/0/2, gi1/0/3) but dont see any traffic from public IPs to private IPs through the other 2 uplink ports 25 and 26.

Please explain to me why this happens and how to handle it?

Thanks.

Moderator

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2.8K Posts

November 14th, 2024 11:21

Hi, please take a look at these importing things to know:

  • Port Monitoring is supported on both physical and logical interfaces like virtual area network (VLAN) and port-channel.
  • The monitored (the source) and monitoring ports (the destination) must be on the same switch.
  • In general, a monitoring port should have no ip address and no shutdown as the only configuration.  A monitoring port also may not be a member of a VLAN.
  • There may only be one destination port in a monitoring session.
  • A Port monitoring session can have multiple source statements.
  • One Destination Port can be used in multiple sessions.

Moderator

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3.9K Posts

November 14th, 2024 01:51

Hi,

 

Can you do a show tech for the configuration, it's probably a configuration issue. Also, what firmware version are you on?

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November 14th, 2024 02:01

Hi,

This is configuraion of 2 interfaces Te1/0/25, Te1/0/26 and firmware version.

Please check for me soon.

Thanks.

Moderator

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3.9K Posts

November 14th, 2024 04:09

Hi,

 

The pictures are quite in low quality. I think I can roughly see what's the configuration. 

 

Can you try creating a different session for the port channel group, to separate from the physical group. I think you cannot mix both logical and physical on a single session. 

 

Try:

 

Switch(config)# monitor session 2 source interface port-channel 1
Switch(config)# monitor session 2 destination interface gi1/0/32

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November 14th, 2024 08:19

@DELL-Joey C​ 

Hi,

This switch model, DELL EMC N1148T-ON only allow me create one monitor session. I can't create second session for monitoring.

Moderator

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3.9K Posts

November 14th, 2024 09:45

Hi,

 

I do not have the switch model to check on the issue, would you mind issue a command #monitor session ? to see how many sessions can be input. Usually is shown <1-4>

 

If this is not possible to add more session, could you remove physical interface from the session and only remain the port channel to check if the issue still remain. 

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November 14th, 2024 10:23

@DELL-Joey C​ 

Hi,

In picture below, i tried to type #monitor session 0, and the output is "Value is out of range. The valid range is 1 to 1". That means I can only have have 1 session monitored.

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November 14th, 2024 11:30

@DELL-Erman O​ 

Hi,

Thanks for your reply. My configuration fully satisfies the requirement you gave, however on the monitoring device I only see internal traffic through the GigabitEthernet ports without seeing traffic information on TerabitEthernet ports from outside through the 2 uplink ports on Switch devices connected to Peplink.

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