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Nexus 3K not learning mac address


Having an issue on 2 new 3048's where mac addresses from servers connected to the TOR are not being leanred by the NX 3048.

Software Version:

  BIOS:      version 1.2.0

  loader:    version N/A

  kickstart: version 5.0(3)U3(2a)

  system:    version 5.0(3)U3(2a)

Example "show interface status":


Port          Name               Status    Vlan      Duplex  Speed   Type


Eth1/1        --                 connected 462       full    1000    1gb       

Eth1/2        --                 connected 462       full    1000    1gb       

Eth1/3        --                 connected 462       full    1000    1gb       

Eth1/4        --                 connected 462       full    1000    1gb    

Example MAC's learned on Po1 channel (which is using (2) 10GB links to a Nexus 7010 pair in typical fashion, and using vPC)


        * - primary entry, G - Gateway MAC, (R) - Routed MAC, O - Overlay MAC

        age - seconds since first seen,+ - primary entry using vPC Peer-Link

   VLAN     MAC Address      Type      age     Secure NTFY    Ports         


* 582      0000.0c9f.f065    dynamic   30140      F    F  Po1

* 582      0000.0c9f.f066    dynamic   30140      F    F  Po1

* 582      0001.d7e6.ba48    dynamic   30140      F    F  Po1

* 582      0001.d7e7.dc47    dynamic   30140      F    F  Po1

* 582      0017.0f7b.6400    dynamic   30140      F    F  Po1

* 582      001d.4675.8c00    dynamic   30140      F    F  Po1

* 582      001e.68ee.d15a    dynamic   30080      F    F  Po1

* 582      001e.68ee.d5c4    dynamic   30020      F    F  Po1

* 582      001e.68ee.d6fe    dynamic   30090      F    F  Po1

... but when trying to find anything locally on the ports assigned, it finds nothing:

dc1-34x-1-43# sh mac address-table | in Eth1/


The Vlans are added properly (and even used 'no shut' when adding them):

dc1-34x-1-43# sh vlan

462      active    Po1, Eth1/1, Eth1/2, Eth1/3

                                                Eth1/4, Eth1/5, Eth1/6, Eth1/7

                                                Eth1/8, Eth1/9, Eth1/10, Eth1/11

Port assignments are correct:

dc1-34x-1-43# sh run int Eth1/3

interface Ethernet1/3

  no cdp enable

  switchport access vlan 462

  spanning-tree port type edge

  negotiate auto

  no snmp trap link-status

  no shutdown

These features are enabled:

version 5.0(3)U3(2a)

no feature telnet

no telnet server enable

feature tacacs+

feature udld

feature interface-vlan

feature lacp

feature lldp

and the mac address time out is set to 14410:

mac address-table aging-time 14410

Servers are properly connected (confirmed) and servers show MAC address when queried fomr the serial port.

Some informaiton to know:

a) This is a rack moved from one Data Center to another, but the TORs were replaced with Nexus 3048's (from another vendor model)

b) These servers are bare metal, no OS installed (which is why I need the MACs)

c) Both TORs show the same exact symptoms and have the exact same confgi (minus IP, etc)

d) The copp policies are exactly the same as other (working) TORs - and I see no filtering for macs (L2) anywhere

e) There are no ACL's configured for blocking this type traffic

Is there something I'm missing?

Is there a command(s) I can run to see if the TOR gets ANY MAC fomr any edge port thats an access vlan?

Is there a command to determine if I am indeed getting blocked by an ACL or filter? (and yes I know "sh ip access-list")

Anything else a CCIE level person can determine (with knowledge of NX-OS)?





Did you ever found the root cause of this issue? I'm currently facing a similar issue on an Nexus 34180YC connected to a ASR1001.

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