> On Sun, Aug 06, 2023 at 05:17:23PM +0800, Jon Smart wrote: >> It's a VPS provided by a local ISP. The VPS has a static IPv4. >> Do you know how to know if /etc/resolv.conf is modified by dhcp? > > The first thing you could do is check whether a DHCP client daemon > is running. That's usually a sign. > > Failing that, find out what your primary network interface's name is, > and then find out how that network interface is brought up. In a server > configuration, it's *usually* brought up by a stanza in the > /etc/network/interfaces file. If that stanza consists of a line > ending with "dhcp", then voila. > > If the primary network interface is not configured in /e/n/i then the > second most likely configuration is NetworkManager. Usually if NM > is in the picture, /etc/resolv.conf will be a symlink, and you will > see evidence of NM both in the symlink's target, and in the contents > of the file. Thus, > > ls -ld /etc/resolv.conf > cat /etc/resolv.conf > > Both of these should give you hints, if NM is involved. > >
Yes my system is exactly using NM for networking. so resolv.conf is just a symlink. I delete that symlink and create a real file, put content into it (no chattr needed), and reboot the OS everything works fine now. regards.