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Bug #4284

PFSense 2.2. won't automatically add arp entries from multicast mac addresses into its arp table

Added by Jonathan Black almost 5 years ago. Updated over 4 years ago.

Status:
Rejected
Priority:
Very High
Assignee:
-
Category:
-
Target version:
-
Start date:
01/24/2015
Due date:
% Done:

0%

Estimated time:
Affected Version:
2.2
Affected Architecture:
i386

Description

I have a cluster created with Windows Network Load Balancing using the IGMP multicast. Anyway, the cluster IP has a multicast mac address (Starts with 01:00:5E).

I captured all arp traffic and found this:

20:44:34.230555 ARP, Request who-has 192.168.1.10 tell 192.168.1.5, length 28
20:44:34.230777 ARP, Reply 192.168.1.10 is-at 01:00:5e:40:01:0a, length 46
20:44:34.230779 ARP, Reply 192.168.1.10 is-at 01:00:5e:40:01:0a, length 46
20:44:35.313687 ARP, Request who-has 192.168.1.10 tell 192.168.1.5, length 28
20:44:35.313908 ARP, Reply 192.168.1.10 is-at 01:00:5e:40:01:0a, length 46
20:44:35.313915 ARP, Reply 192.168.1.10 is-at 01:00:5e:40:01:0a, length 46
20:44:36.067167 ARP, Request who-has 192.168.1.10 tell 192.168.1.5, length 28
20:44:36.067478 ARP, Reply 192.168.1.10 is-at 01:00:5e:40:01:0a, length 46
20:44:36.067853 ARP, Reply 192.168.1.10 is-at 01:00:5e:40:01:0a, length 46
20:44:37.216105 ARP, Request who-has 192.168.1.10 tell 192.168.1.5, length 28
20:44:37.216322 ARP, Reply 192.168.1.10 is-at 01:00:5e:40:01:0a, length 46
20:44:37.216329 ARP, Reply 192.168.1.10 is-at 01:00:5e:40:01:0a, length 46
20:44:38.143842 ARP, Request who-has 192.168.1.10 tell 192.168.1.5, length 28
20:44:38.144042 ARP, Reply 192.168.1.10 is-at 01:00:5e:40:01:0a, length 46
20:44:38.144044 ARP, Reply 192.168.1.10 is-at 01:00:5e:40:01:0a, length 46
20:44:39.152743 ARP, Request who-has 192.168.1.10 tell 192.168.1.5, length 28
20:44:39.152966 ARP, Reply 192.168.1.10 is-at 01:00:5e:40:01:0a, length 46
20:44:39.153091 ARP, Reply 192.168.1.10 is-at 01:00:5e:40:01:0a, length 46
20:44:40.166170 ARP, Request who-has 192.168.1.10 tell 192.168.1.5, length 28
20:44:40.166387 ARP, Reply 192.168.1.10 is-at 01:00:5e:40:01:0a, length 46
20:44:40.166393 ARP, Reply 192.168.1.10 is-at 01:00:5e:40:01:0a, length 46

However the mac address never makes it into the ARP table. I added the mac address manually from the command line by running: arp -S 192.168.1.10 01:00:5e:40:01:0a and then the PFSense firewalls could ping 192.168.1.10

History

#1 Updated by Jonathan Black almost 5 years ago

This can be permanently fixed on each PFSense Firewall by:

System->Advanced->System Tunables

Then add an entry for "net.link.ether.inet.allow_multicast" and set its value to 1.

This was not an issue in 2.1.5.

#2 Updated by Chris Buechler almost 5 years ago

  • Status changed from New to Rejected

that'll be required to add as a tunable where you need that to work. The fact it worked before was technically the bug, acting in violation of RFC 1812.

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.

What 2.2 does by default is the correct behavior.

#3 Updated by Sam Bingner over 4 years ago

This should probably be added to System-Advanced Network then so people can actually find this to fix it

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