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Description of problem:
If NM controls interface on which ipv6 initialization is enabled (IPV6INIT=yes)
it's setting these options to 0

net.ipv6.conf.enp0s25.accept_ra_defrtr = 0
net.ipv6.conf.enp0s25.accept_ra_pinfo = 0
net.ipv6.conf.enp0s25.accept_ra_rtr_pref = 0

once this is set machine ignores default routes from router advertisements and this further prohibits communication.


Version-Release number of selected component (if applicable):
NetworkManager-1.0.6-29.el7_2.x86_64

How reproducible:
Always 

Steps to Reproduce:
1. Install 7.2 GA 
2. Install NetworkManager-1.0.6-29.el7_2.x86_64
3. make sure your interface is handled by NM and IPV6INIT is enabled (it's by default)
4. restart NetworkManager or OS

Actual results:
Following kernel parameters are disabled once NM controls them

net.ipv6.conf.enp0s25.accept_ra_defrtr = 0
net.ipv6.conf.enp0s25.accept_ra_pinfo = 0
net.ipv6.conf.enp0s25.accept_ra_rtr_pref = 0

even though accept_ra is still enabled 

net.ipv6.conf.enp0s25.accept_ra = 1  


Expected results:
acc. documentation and its functional default definitions these parameters should be enabled if accept_ra is enabled.

https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt

Additional info:

(In reply to Rastislav Hepner from comment #0)
> Description of problem:
> If NM controls interface on which ipv6 initialization is enabled
> (IPV6INIT=yes)
> it's setting these options to 0
>
> net.ipv6.conf.enp0s25.accept_ra_defrtr = 0
> net.ipv6.conf.enp0s25.accept_ra_pinfo = 0
> net.ipv6.conf.enp0s25.accept_ra_rtr_pref = 0

This is normal and expected as NM implements IPv6 autoconfiguration in
userspace and so it disables some IPv6 RA-related options in
kernel.

> once this is set machine ignores default routes from router advertisements
> and this further prohibits communication.

Is it only a problem of missing routes or also IPv6 addresses are not
configured? Can you please attach the connection profile, NM logs (if
possible at DEBUG level), and the output of "ip -6 r; ip a" after the
connection is established? Thanks!

As explained in comments above accept_ra_defrtr must be set to 0 during NM operation. I'm closing this, please reopen if needed.