[CentOS] Centos 7.3.1611 - NetworkManager + dhcp + ipv6

Diaulas Castro

diaulas.castro at opencloudfactory.com
Tue Mar 21 19:51:04 UTC 2017


Used steps on sysctl from Centos7 FAQ (https://wiki.centos.org/FAQ/CentOS7) and some gathered on internet

# cat /etc/sysctl.d/90-disable_ipv6.conf 
net.ipv6.conf.all.disable_ipv6=1
net.ipv6.conf.default.disable_ipv6=1
net.ipv6.conf.eth0.disable_ipv6=1
net.ipv6.conf.eth1.disable_ipv6=1
net.ipv6.conf.all.use_tempaddr=0
net.ipv6.conf.all.autoconf=0
net.ipv6.conf.all.accept_ra=0
net.ipv6.conf.default.autoconf=0
net.ipv6.conf.default.accept_ra=0
net.ipv6.conf.eth0.autoconf=0
net.ipv6.conf.eth1.autoconf=0


But with dhcp, NetworkManager (or something) reenables ipv6 on interfaces.

#sysctl -a | grep ipv6 | grep disable
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.eth0.disable_ipv6 = 0
net.ipv6.conf.eth1.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1

And the interface gets the ipv4 but still have temporary ipv6 on it (our dhcp doesnt support ipv6)

# ip a s eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000
    link/ether 00:0c:29:31:5a:9d brd ff:ff:ff:ff:ff:ff
    inet 10.10.216.247/24 brd 10.10.216.255 scope global dynamic eth0
       valid_lft 451sec preferred_lft 451sec
    inet6 fe80::20c:29ff:fe31:5a9d/64 scope link 
       valid_lft forever preferred_lft forever

And this bugs  my use for ovftool with the option "--X:waitForIp" because it's returns (mostly of times) the ipv6 addr

It's a bug, missing documentation or my 






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