Multicast MAC and Static ARP

[dean.pecorari]

We have a Checkpoint Cluster XL firewall in a software load balancing environment.

To get our switches to recognise the multicast mac address used for load balancing function we have had to configure a static arp entry.

Is there any other feasible way to avoid having to configure static arp entries ??? such configuring IGMP

[ashok_boin]

Hi,

Are you talking about Cisco switches?

If that is the case, you can use CGMP protocol.

Thank you,

-Ashok.

[alagrawa]

Hi Dean,

The checkpoint cluster most probably has a virtual unicast ip address mappped to a virtual multicast mac address.

Cisco adheres to RFC1812, "Requirements for IP Version 4 Routers," which states ...

"A router MUST not believe any ARP reply that claims that the Link Layer address of another host

or router is a broadcast or multicast address."

If the solution (Firewalls, Load-Balancers, etc.) requires the router to send packets to a Layer 3 unicast IP address using a Layer 2 multicast MAC address...the router must be configured with a static ARP entry.

If this is the case with your checkpoint cluster, then the only workaround is to configure static arp entries.

hope this helps.

regards

-alok