Bug 752097

Summary: kernel: bond interfaces sending false arp replies
Product: Red Hat Enterprise Linux 4 Reporter: michael.gruener
Component: kernelAssignee: Veaceslav Falico <vfalico>
Status: CLOSED NOTABUG QA Contact: Red Hat Kernel QE team <kernel-qe>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 4.9CC: agospoda, peterm, vgoyal
Target Milestone: rc   
Target Release: ---   
Hardware: i686   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2011-11-21 14:03:47 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Attachments:
Description Flags
Packet dumps of two affected systems none

Description michael.gruener 2011-11-08 14:49:29 UTC 
Description of problem:

When configuring multiple bond interfaces (active-backup mode) on one system, all interfaces reply to arp requests for any ip adress configured on the interfaces.

example setup:

bond0 = 10.10.145.131 (00:21:5a:f3:fe:ce)
bond0:1 = 10.10.145.132
bond1 = 10.10.146.131 (00:21:5a:f3:fe:cc)

An arp request "Who has 10.10.145.131? Tell xxx.xxx.xxx.xxx" would (sometimes) be answered with two replies "10.10.145.131 is at 00:21:5a:f3:fe:ce" and "10.10.145.131 is at 00:21:5a:f3:fe:cc".

We have four systems showing this behavior and on each system the problem started after upgrading the kernel-smp from 2.6.9-89.33.1 to 2.6.9-101.

I have attached four pcap files showing the arp requests of the two bonding interfaces of two systems right after clearing the arp cache.

Version-Release number of selected component (if applicable):
kernel-smp-2.6.9-101.EL

  
Actual results:
See attached archive.


Expected results:
Only interfaces with the correct ip address should respond to arp requests asking for this ip.
Comment 1 michael.gruener 2011-11-08 14:52:03 UTC 
Created attachment 532302 [details]
Packet dumps of two affected systems
Comment 2 Andy Gospodarek 2011-11-10 21:44:10 UTC 
This sounds more like a chance to the sysctl option 'net.ipv4.conf.default.arp_ignore' than a bonding change, but we can take a look.
Comment 3 michael.gruener 2011-11-21 09:42:59 UTC 
Setting net.ipv4.conf.default.arp_ignore = 1 solved the problem.
Comment 4 Andy Gospodarek 2011-11-21 14:03:47 UTC 
Great!  Closing at NOTABUG.