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Anthony's avatar
Anthony
Icon for Nimbostratus rankNimbostratus
Feb 14, 2014

ifconfig returns different MAC address to GUI

Hi all, I'm going through a project to reconfigure a pair of our LTMs, and I'm seeing some strangeness with regards to MAC addresses.

 

Whats reported in the interfaces list in the GUI doesn't match what I see if I run 'ifconfig' from the command line.

 

Does anyone have an idea as to why this might be?

 

Thanks, Ant

 

management

5 Replies

  • Cory_50405's avatar
    Cory_50405
    Icon for Noctilucent rankNoctilucent
    Feb 14, 2014

    Some information pertaining to how BIG-IP handles MAC addressing can be found here:

     

    http://support.f5.com/kb/en-us/solutions/public/14000/500/sol14513.html

     

  • Anthony's avatar
    Anthony
    Icon for Nimbostratus rankNimbostratus
    Feb 14, 2014

    Thanks for the link Cory.

    So this is what I have

    1.1 - internal VLAN
1.2 - external VLAN
1.3 - HA VLAN

    I've had a look using the command: tmsh show sys mac-address and get this back (filtered for relevance)

     0:23:e9:54:5c:1    net interface          mgmt                   mac-address
 0:23:e9:54:5c:3    net vlan               internal               mac-true
 0:23:e9:54:5c:4    net interface          1.1                    mac-address
 0:23:e9:54:5c:4    net vlan               external               mac-true
 0:23:e9:54:5c:5    net interface          1.2                    mac-address
 0:23:e9:54:5c:5    net vlan               HA                     mac-true
 0:23:e9:54:5c:6    net interface          1.3                    mac-address

    ifconfig gives:

    eth0      Link encap:Ethernet  HWaddr 00:23:E9:54:5C:01
internal  Link encap:Ethernet  HWaddr 00:23:E9:54:5C:03
external  Link encap:Ethernet  HWaddr 00:23:E9:54:5C:04
HA        Link encap:Ethernet  HWaddr 00:23:E9:54:5C:05

    Interfaces in GUI gives:

    1.1     0:23:e9:54:5c:4     1000    1   
1.2     0:23:e9:54:5c:5     1000    1   
1.3     0:23:e9:54:5c:6     1000    1
  • Cory_50405's avatar
    Cory_50405
    Icon for Noctilucent rankNoctilucent
    Feb 14, 2014

    This is expected behavior. From the solution article I linked:

     

    When a VLAN is created, a MAC address from the pool is assigned to the VLAN. When assigning a MAC address to the VLAN, the BIG-IP system may re-use a MAC address that was also assigned as one of the interface MAC addresses. The BIG-IP system uses this MAC address to pass L3 or above traffic.

     

  • Anthony's avatar
    Anthony
    Icon for Nimbostratus rankNimbostratus
    Feb 14, 2014

    Oh right. I will forward that on to our Network guys and see if that helps to clear anything up, or if there is configuration elsewhere which may need to be clarified.

     

    I'll report back on my findings asap...

     

    Thanks Ant

     

  • Anthony's avatar
    Anthony
    Icon for Nimbostratus rankNimbostratus
    Feb 20, 2014

    It seems that all was ok in the end and a bit of work was identified around the switches and existing cabling to get this working. All has been resolved now with no issue around the MAC addresses.