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Daniel_Demers_1's avatar
Daniel_Demers_1
Icon for Nimbostratus rankNimbostratus
Jul 30, 2014

F5 Interface giving wrong mac-address to switch

Hello,

 

I have a F5 1600 LTM which has 2 interfaces UP and 2 interfaces DOWN as depcited in image.

 

 

Also when looking at our Firewall which has the gateway for the subnet and has an interface trunking to a switch VLAN in which case that same VLAN is trunked to port 1.1 of our F5 I find the wrong mac address.

 

 

The mac address being recorded ends in 2906 but the F5 states that is for 1.3 which is DOWN and I have verified has no physical connection to anything. So I am curious why this is happening. I started to look into this when I was creating documentation on how our QA environment worked....where this F5 sits when trying to map the flow of data revealed the wrong mac address was being used when going out onto the VLAN.

 

Dan

 

application delivery
deployment
design
LTM
management

2 Replies

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  • mimlo_61970's avatar
    mimlo_61970
    Icon for Cumulonimbus rankCumulonimbus
    Jul 30, 2014

    The MAC address used is actually determined by the VLAN, not the physical interface. Whatever vlan you have assigned to this interface is what will be used. You can also specify a MAC Masquerade Address, which will then override the VLAN MAC.

     

  • shaggy's avatar
    shaggy
    Icon for Nimbostratus rankNimbostratus
    Jul 30, 2014

    If you go to the Network | VLANs section in the configuration utility, and click on one of the VLANs in question, it should show what MAC address it is using. What mimlo said above is correct - do you have a MAC-masquerade address assigned to the VLAN or traffic-group (depending on your code level)?