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Monitor the Used Vlans in a Trunk

lomonaco
Level 1
Level 1

Hi guys,

I have a lot of trunks to connect my switches to servers. Now we permit all the vlans in those trunks...

I wanna to limit the vlans in the trunk but first I wanna to discover what vlans the servers are using..

So my questions is: is there any show command or some monitor or span configuration where I can find the vlans that my server are really using

I wanna to avoid have to ask the servers team what 802.1q configuration did they do in the NICs in each server

Thanks a Lot

My Best Regards,

Andre Lomonaco

1 Reply 1

Jon Marshall
Hall of Fame
Hall of Fame

lomonaco wrote:

Hi guys,

I have a lot of trunks to connect my switches to servers. Now we permit all the vlans in those trunks...

I wanna to limit the vlans in the trunk but first I wanna to discover what vlans the servers are using..

So my questions is: is there any show command or some monitor or span configuration where I can find the vlans that my server are really using

I wanna to avoid have to ask the servers team what 802.1q configuration did they do in the NICs in each server

Thanks a Lot

My Best Regards,

Andre Lomonaco

Andre

Simplest way would be to ask your server team what IP addresses the server is using and then map to your vlans ie. each vlan will have a subnet. If you don't want to do that then look at the mac-address table on the switch a server is connected, get the mac-address(es) associated with the port for the server and then match up the mac-address(es) with the IP address in your arp table on the L3 device that is responsible for routing the vlans.

Jon

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