I upgraded my F21 boxes to F23 this weekend. While doing so I noticed an odd problem on one, which was still running network.service. It has this in its ifcfg-eth0 file:
but on boot and whenever restarting network.service , resolv.conf would be overwritten by dhclient-script (it was definitely dhclient-script doing it - the file had the 'generated by /usr/sbin/dhclient-script' text added). PEERDNS="no" is explicitly supposed to prevent that. I switched from network.service to NetworkManager.service and this stopped happening, with NM it works fine.
I'm filing against dhcp at Lukáš Nykrýn's suggestion - https://bugzilla.redhat.com/show_bug.cgi?id=1093777#c11 - but it's also possible that the issue may really be in the network scripts somewhere.
CCing Lukáš for the initscripts stuff.
Thanks. Few months ago I've removed  dhclient's dependency on initscripts by copying necessary functions from /etc/sysconfig/network-scripts/network-functions and /etc/rc.d/init.d/functions into dhclient-script. I was not sure about source_config(), but now I see we need it because of the PEERDNS.
Should be fixed with .
dhcp-4.3.3-6.fc23 has been submitted as an update to Fedora 23. https://bodhi.fedoraproject.org/updates/FEDORA-2015-beefdd098b
dhcp-4.3.3-6.fc23 has been pushed to the Fedora 23 testing repository. If problems still persist, please make note of it in this bug report.
If you want to test the update, you can install it with
$ su -c 'dnf --enablerepo=updates-testing update dhcp'
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2015-beefdd098b
dhcp-4.3.3-6.fc23 has been pushed to the Fedora 23 stable repository. If problems still persist, please make note of it in this bug report.