ipv6 Autoconfiguration not working on CentOS 7

Issues related to configuring your network
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gkaur2
Posts: 3
Joined: 2017/10/10 11:09:45

ipv6 Autoconfiguration not working on CentOS 7

Post by gkaur2 » 2017/10/10 11:21:14

Hi all,

I am trying to autoconfigure IPv6 using SLAAC. But i can that my ipv6 address is still local-link address.

eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 10.97.51.246 netmask 255.255.255.0 broadcast 10.97.51.255
inet6 fe80::250:56ff:fe8c:7b58 prefixlen 64 scopeid 0x20<link>
ether 00:50:56:8c:7b:58 txqueuelen 1000 (Ethernet)
RX packets 12122157 bytes 2539589464 (2.3 GiB)
RX errors 0 dropped 2358 overruns 0 frame 0
TX packets 152674 bytes 41222749 (39.3 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

I have edited /etc/suysconfig/network-scripts/ifcfg-eth0 as below:

DEVICE=eth0
TYPE=Ethernet
UUID=f99a59cd-f40b-4109-aaf0-db78b1906581
ONBOOT=yes
NM_CONTROLLED=yes
BOOTPROTO=none
IPADDR=10.97.51.246
NETMASK=255.255.255.0
GATEWAY=10.97.51.1
IPV6INIT=yes
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=eth0
PEERDNS=yes
PEERROUTES=yes
IPV6_PEERDNS=yes
IPV6_PEERROUTES=yes

Also i can see that IPv6 support is enabled by default so kernel parameters are also set as below:
net.ipv6.conf.all.autoconf = 1
net.ipv6.conf.all.accept_ra = 1

I have also tried disabling firewalld but still no progress. If i install CentOS 6 on same vm, it is working fine with the same router.
Please suggest if i am missing something?

gkaur2
Posts: 3
Joined: 2017/10/10 11:09:45

Re: ipv6 Autoconfiguration not working on CentOS 7

Post by gkaur2 » 2017/11/01 08:22:14

To add more, Using same network configuration ipv6 is working fine and global ip address is assigned to eth0 when Network Manager is UP but on disabling it and only using network service, it is not working anymore.
Can anyone suggest how i can use ipv6 autoconfig using only netwrok service?

User avatar
jlehtone
Posts: 4523
Joined: 2007/12/11 08:17:33
Location: Finland

Re: ipv6 Autoconfiguration not working on CentOS 7

Post by jlehtone » 2017/11/02 08:19:22

Code: Select all

NM_CONTROLLED=yes
Tells the network.service that this interface is not its problem. However, then the interface should stay entirely down without NM.

IMHO, there are two valid strategies:
1. Disable network.service and use only the NM
2. Uninstall the NM packages and use only the network.service
The default is probably:
3. Have both NM and network.service enabled

The #3 has too many suspects to meddle with.

Personally, I've used the #1 successfully. IPv6 too -- at home as ISP supports it -- but not sure if it is SLAAC.


Did the CentOS 6 have NM messing up, or a "pure" ifcfg-eth0? Do you have a copy of that config?

gkaur2
Posts: 3
Joined: 2017/10/10 11:09:45

Re: ipv6 Autoconfiguration not working on CentOS 7

Post by gkaur2 » 2017/11/09 07:05:41

Thanks for helping out. My issue resolved. Enabling Network Manager Service and disabling Network service brought it up :)

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