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Forum Discussion

Yugandhar's avatar
Yugandhar
Icon for Nimbostratus rankNimbostratus
Nov 02, 2018

Reg MAC Address for a Virtual Server.

Hi,   Would like to know how a MAC address is assigned to a Virtual Server in active-standby setup, as I observe multiple virtual servers with in the same vlan share same MAC address.   Below i...
application delivery
BIG-IP
LTM
Simon_Blakely's avatar
Simon_Blakely
Icon for Employee rankEmployee
Nov 04, 2018

Each LTM has a physical Mac address that is used for virtual addresses and self-IP addresses that are active on the device.

 

So you will see that all the mac addresses will be the same.

 

K14513: MAC address assignment for interfaces, trunks, and VLANs (11.x - 12.x)

 

After a failover, the new active LTM will send Gratuitous ARPs with it's own mac address for all the virtual addresses that are now active.

 

You can configure Mac Masquerading, where an artificially generated Mac Address is used for virtual addresses and floating Self-IPs. After failover, the new active Device starts responding to the configured Mac Address. This can be faster, but relies on the switch CAM table updating correctly.

 

K13502: Configuring MAC masquerade (11.x - 14.x)