On 02.07.2017 13:16, James Knott wrote:
On 07/02/2017 05:07 AM, Florian Gleixner wrote:
On 01.07.2017 23:17, James Knott wrote:
One thing I've noticed is that when connected via Ethernet & DHCP, openSUSE 42.2 does not use duplicate address detection (RFC 5227) when bringing the connection up. DAD is used to avoid IP address conflicts. On the other hand, Windows 10 does use it. However, DAD is used on 42.2 for link local connections, where it is mandatory, so the code for doing it is there. Any idea why Linux doesn't use DAD on IPv4 DHCP? It's also mandatory on IPv6, using ICMP6 Neighbor Discovery.
When DAD is used, the computer will arp it's assigned address, but with 0.0.0.0 as the source address. If there is no response, it will assume the address is safe to use and then send out a gratuitous arp, to let all the other devices know the address is being used.
I guess you use wicked. Then it should try to detect duplicate IPs.
from
rpm -q --changelog wicked-0.6.40-6.3.1.x86_64 ... * Mi Mai 28 2014 mt@suse.de - version 0.5.27 ... - ipv4: new default to send gratuitous arp Consider new suse ifcfg variable default SEND_GRATUITOUS_ARP=auto for arp-notify, enabling to send gratuitous arp by default, when duplicate IPv4 check is enabled via arp-verify/CHECK_DUPLICATE_IP and the check were successful (bnc#879911,fate#314399).
But probably this is somehow broken?
I also have 0.6.40-6.3.1.
Just checked: I have set: CHECK_DUPLICATE_IP="no" and SEND_GRATUITOUS_ARP="no" in /etc/sysconfig/network/config You should check, what are your settings and try to set them to "yes".