In my test networks at home I've often run into issues with NetworkManager or dhclient messing with my network settings, most importantly the DNS configuration. Judging by the hundreds of StackExchange and other forum posts to the same effect, I'm certainly not alone. The fact that this seems like such a newbie problem just makes it all the more annoying.
I've tried many changes, based on those forum discussions, such as:
- Set NM-CONTROLLED=no in all /etc/sysconfig/networking/ifcfg-* files.
- Set BOOTPROTO=static in all/etc/sysconfig/networking/ifcfg-* files.
- Set DNS1 and SEARCH in all/etc/sysconfig/networking/ifcfg-* files.
- Set dns=none in /etc/NetworkManager/NetworkManager.conf.
- Fully disable NetworkManager from starting.
And funnily enough, things would still be changing my /etc/resolv.conf every time networking was restarted.
Turns out that I am in fact making a RedHat-newbie mistake! I'm stuck in my old ways of manually micro-managing specific settings of a Linux box. I'm so stuck that I've forgotten my lessons from the RHCSA certification: system-config-network-tui.
That tool is great at resetting your network config and overwriting it with the exact setup you want. It helps clear out any settings in odd places that might lead to the continuous mucking about with your settings.
