Bug 1334439

Summary: Unable to disable IPv6 DAD or Optimistic DAD for all interfaces
Product: Red Hat Enterprise Linux 7 Reporter: Michele Baldessari <michele>
Component: kernelAssignee: Matteo Croce <mcroce>
kernel sub component: IPv6 QA Contact: Wei Chen <weichen>
Status: CLOSED ERRATA Docs Contact:
Severity: low    
Priority: low CC: aloughla, atragler, mcroce, mleitner, network-qe, rkhan, sukulkar
Version: 7.3   
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: kernel-3.10.0-764.el7 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2018-04-10 19:25:24 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description Michele Baldessari 2016-05-09 15:45:27 UTC
Description of problem:
The net/ipv6/.*/{accept_dad,optimistic_dad} should be able to be set for
all interfaces by setting
/proc/sys/net/ipv6/default/{accept_dad,optimistic_dad}

This does not work currently (confirmed with Hannes) and the only way to set 
these values is to do it for each interface.

So doing the following won't work:
[root@haa-08 ipv6]# cat /etc/sysctl.d/90-ipv6-disable-dad.conf
net.ipv6.conf.default.optimistic_dad=1                        

The only way to do it is to do it per interface:
net.ipv6.conf.eth0.optimistic_dad=1

The problem with this approach is that you can't really set up a new system
where DAD is fully disabled (or optimistic DAD enabled). You need to know and
set each interface explicitly, which is particularly hard given that we
have predictable naming for interfaces these days.


Version-Release number of selected component (if applicable):
3.10.0-327.13.1.el7.x86_64


Additional info:
This BZ was filed after a discussion in BZ#1245951

Comment 2 Matteo Croce 2017-09-12 15:56:13 UTC
Just posted a patch upstream: https://marc.info/?m=150523120610624

Comment 6 Rafael Aquini 2017-10-31 12:33:14 UTC
Patch(es) committed on kernel repository and an interim kernel build is undergoing testing

Comment 8 Rafael Aquini 2017-11-01 10:35:12 UTC
Patch(es) available on kernel-3.10.0-764.el7

Comment 18 errata-xmlrpc 2018-04-10 19:25:24 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2018:1062