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Gianluca_Bona
Gianluca_Bona
New Member
October 26, 2017
Question

Fortigate and Microsoft NLB in multicast mode

  • October 26, 2017
  • 1 reply
  • 7554 views

Hi guys,

anyone has experience how Fortigate manage the ARP requests to a multicast MAC address (more specific: Microsoft NLB multicast mode)?

I need to put a new Vdom (Routed, not transparent) as default gateway for my servers network and among the servers, there are many with Microsoft NLB in multicast mode.

Currently the default gw is a Cisco Nexus switch L3 and it need to add static ARP entries for each NLB multicast MAC address, because it is confirmed that Microsoft NLB violate the RFC 1812 (http://blog.ipspace.net/2012/05/arp-reply-with-multicast-source-mac-is.html).

How Fortigate manage it? does it support without any special config, or shall I add the same static ARP entries?

thanks a lot!

Gianluca

1 reply

boozely25
boozely25
New Member
February 1, 2018

Did you ever find a solution to this? Did you have to add static mac address entries on your Fortigate. I have run into an issue where we put in a Fortigate 500D(5.6.3) and now a Microsoft Network Load Balanced Webserver cluster keeps losing connectivity to anything outside of it's subnet for about 5 minutes.

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