How to determine if a VLAN is still in use?

[ttrevino1]

I have several vlans that were created as part of a failed NAC implemementation that I'd like to delete. However, I wanted to confirm they weren't in use somewhere? I'm assuming as long as there are no switchports configured in those particular vlans, then they're okay to delete?

When I use the command 'show vlan counters', these vlans are all zeros.

Thanks in advance for the assistance.

#sho vlan

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
200  NAC_VPN_Untrusted                active
 

#show vlan counters

Vlan Id                                            : 200
L2 Unicast Packets                                 : 0
L2 Unicast Octets                                  : 0
L3 Input Unicast Packets                           : 0
L3 Input Unicast Octets                            : 0
L3 Output Unicast Packets                          : 0
L3 Output Unicast Octets                           : 0
L3 Output Multicast Packets                        : 0
L3 Output Multicast Octets                         : 0
L3 Input Multicast Packets                         : 0
L3 Input Multicast Octets                          : 0
L2 Multicast Packets                               : 0
L2 Multicast Octets                                : 0
 

[jj27]

You would need to check all switches, or from your core switch do "show mac address-table vlan 200" and "show ip arp vlan 200"

Those two commands will show you any MACs and IPs learned on that VLAN.  From the MAC address command, you might see a few that are listed as CPU for the ports which you can ignore.

[ttrevino1]

Something odd I'm seeing, when I look at this vlan, I see all these ports listed, however, some are regular switchport access ports, on specific vlans, not trunk ports. Is this what I should be seeing? Also, when I use the second command, you can see it craps out at the word vlan. But this only happens when looking at vlan 200. When I look at other vlans that I know aren't used anymore, but still configured, the command works fine. I'm thinking this is happening because vlan 200 isn't configured as an interface vlan?

Switch#sho mac-address-table vlan 200
Legend: * - primary entry
        age - seconds since last seen
        n/a - not available

  vlan   mac address     type    learn     age              ports
------+----------------+--------+-----+----------+--------------------------
*  200  3333.0000.000d    static  Yes          -   Gi1/1,Gi1/2,Gi1/3,Gi3/1
                                                   Gi3/3,Gi3/8,Gi3/11,Gi3/12
                                                   Gi3/13,Gi3/14,Gi3/15,Gi3/16
                                                   Gi7/2,Gi7/3,Gi7/4,Gi7/9
                                                   Gi7/11,Gi7/13,Gi7/14,Gi7/15
                                                   Gi7/18,Gi7/19,Gi7/21,Gi7/22
                                                   Gi7/23,Gi7/24,Gi7/25,Gi7/26
                                                   Gi7/27,Gi7/28,Gi7/29,Gi7/31
                                                   Gi7/32,Gi7/35,Gi7/36,Gi7/37
                                                   Gi7/39,Gi7/40,Gi7/41,Gi7/42
                                                   Gi7/43,Gi8/2,Gi8/3,Gi8/4
                                                   Gi8/5,Gi8/12,Gi8/14,Gi8/17
                                                   Gi8/18,Gi8/19,Gi8/26,Gi8/28
                                                   Gi8/33,Gi8/34,Gi8/35,Gi8/36
                                                   Gi8/37,Gi8/38,Gi8/39,Gi8/40
                                                   Gi8/43,Gi8/45,Gi9/1,Gi9/2
                                                   Gi9/3,Gi9/4,Gi9/6,Gi9/7
                                                   Gi9/10,Gi9/11,Gi9/12,Gi9/14
                                                   Gi9/15,Gi9/16,Po257,Router
                                                   Switch,Stby-Switch
*  200  3333.0000.0001    static  Yes          -   Switch,Stby-Switch
*  200  3333.0000.0016    static  Yes          -   Switch,Stby-Switch

Switch#sho ip arp vlan 200
Translating "vlan"
                         ^
% Invalid input detected at '^' marker.

Switch#sho ip arp vlan 6
Protocol  Address          Age (min)  Hardware Addr   Type   Interface
Internet  10.6.7.8              -   (scrubbed) ARPA   Vlan6