[CentOS] systemd-networkd issue

Wed Oct 4 06:20:37 UTC 2017
Phil Perry <pperry at elrepo.org>

On 04/10/17 03:46, Phil Manuel wrote:
> Hi,
> If I disable ipv6 via the kernel command line, ipv6.disable=1, then
> systemd-networkd fails to bring up any interfaces.
> Removing the option and networking works as expected.
> Phil.

How are you controlling your network interfaces? I am using NM.

Whilst not answering your question directly, I disable ipv6 in 

cat  /etc/sysctl.conf
# sysctl settings are defined through files in
# /usr/lib/sysctl.d/, /run/sysctl.d/, and /etc/sysctl.d/.
# Vendors settings live in /usr/lib/sysctl.d/.
# To override a whole file, create a new file with the same in
# /etc/sysctl.d/ and put new settings there. To override
# only specific settings, add a file with a lexically later
# name in /etc/sysctl.d/ and put new settings there.
# For more information, see sysctl.conf(5) and sysctl.d(5).
net.ipv4.ip_forward = 1
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1

After updating, run 'sysctl -p' and 'dracut -f'

Works for me.