Description of problem:

With NetworkManager version "NetworkManager-1.42.2-6.el9_2.x86_64" IPv6 is enabled on LoopBackup device even after /etc/sysctl.conf settings are configured to disable IPv6 on all devices. Same issue did not exist with earlier version of NetworkManager.

After applying sysctl setting "sysctl -p" loopback IPv6 get disabled but after reboot its come back enabled.

I did not had similar issue with previous version of NetworkManager with RedHat 9.

1. disable ipv6
   net.ipv6.conf.all.disable_ipv6 = 1
   net.ipv6.conf.default.disable_ipv6 = 1

Version-Release number of selected component (if applicable):

NetworkManager-1.42.2-6.el9_2.x86_64

How reproducible:

Steps to Reproduce:
1. Update /etc/sysctl.conf to disable all interfaces IPv6.

1. disable ipv6
   net.ipv6.conf.all.disable_ipv6 = 1
   net.ipv6.conf.default.disable_ipv6 = 1

2. sysctl -p
3. reboot

Ipv6 is enabled again by NetworkManager even /etc/sysctl.conf settings are configured to disable on all Devices.

Actual results:

IPv6 is enabled on lo device with newer NetworkManager version.

Expected results:

Disable IPv6 on lo device.

Additional info: