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#1 2022-09-28 18:39:28

amir.gi73
Member
Registered: 2018-09-30
Posts: 4

[solved] resolv.conf resets by networkmanager

I'm using NetworkManager, systemd-resolved and expressvpn (official package).
expressvpn sets it's own DNS servers in /etc/resolv.conf when establishing a connection. When I connect to expressvpn everything is fine and DNS Adresses set accourdingly. After a few minutes my net won't work and when I check /etc/resolv.conf, Networkmanager hat reseted the DNS and set it to 127.0.0.1:53. I'm assuming this happens because of a connection drop. Using Fedora/Ubuntu/... never hat this problem. So I'm assuming that my network configuration is problematic.

/etc/NetworkManager/NetworkManager.conf
# Configuration file for NetworkManager.
# See "man 5 NetworkManager.conf" for details.


[keyfile]
/etc/NetworkManager/conf.d/00-dhclient.conf
[main]
# Choose a DHCP client below.  Upstream recommends dhclient, but results may vary.
# dhcpcd is the DHCP client usually used by Slackware:
# dhcp=dhcpcd
# dhclient is the ISC reference DHCP client, part of the dhcp package:
dhcp=dhclient
# This is a simple DHCP client that is built into NetworkManager:
# dhcp=internal
/etc/NetworkManager/conf.d/dns.conf
[main]
dns=systemd-resolved
/etc/systemd/resolved.conf 
[Resolve]
# Some examples of DNS servers which may be used for DNS= and FallbackDNS=:
# Cloudflare: 1.1.1.1#cloudflare-dns.com 1.0.0.1#cloudflare-dns.com 2606:4700:4700::1111#cloudflare-dns.com 2606:4700:4700::1001#cloudflare-dns.com
# Google:     8.8.8.8#dns.google 8.8.4.4#dns.google 2001:4860:4860::8888#dns.google 2001:4860:4860::8844#dns.google
# Quad9:      9.9.9.9#dns.quad9.net 149.112.112.112#dns.quad9.net 2620:fe::fe#dns.quad9.net 2620:fe::9#dns.quad9.net
#DNS=
#FallbackDNS=1.1.1.1#cloudflare-dns.com 9.9.9.9#dns.quad9.net 8.8.8.8#dns.google 2606:4700:4700::1111#cloudflare-dns.com 2620:fe::9#dns.quad9.net 2001:4860:4860::8888#dns.google
#Domains=
#DNSSEC=no
#DNSOverTLS=no
#MulticastDNS=yes
#LLMNR=yes
#Cache=yes
#CacheFromLocalhost=no
#DNSStubListener=yes
#DNSStubListenerExtra=
#ReadEtcHosts=yes
#ResolveUnicastSingleLabel=no
ip link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp2s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN mode DEFAULT group default qlen 1000
    link/ether ------------ brd ff:ff:ff:ff:ff:ff
3: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DORMANT group default qlen 1000
    link/ether ------------ brd ff:ff:ff:ff:ff:ff

Last edited by amir.gi73 (2022-09-29 10:37:04)

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#2 2022-09-28 19:12:13

seth
Member
Registered: 2012-09-03
Posts: 50,012

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#3 2022-09-29 10:36:16

amir.gi73
Member
Registered: 2018-09-30
Posts: 4

Re: [solved] resolv.conf resets by networkmanager

I've seen this in the Wiki. Thought with "no dns" it won't work in my setup. After you mentioned it, I tested it and it seems to work.
Thanks.

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#4 2022-09-29 12:09:15

Morta
Member
Registered: 2019-07-07
Posts: 655

Re: [solved] resolv.conf resets by networkmanager

You can protect resolv.conf to be overwritten with sudo chattr +x /etc/resolv.conf

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#5 2022-09-29 14:06:24

seth
Member
Registered: 2012-09-03
Posts: 50,012

Re: [solved] resolv.conf resets by networkmanager

a) That's not a good approach to control the behavior, you're inducing failures
b) https://man.archlinux.org/man/core/e2fs … hattr.1.en - why do you think direct access would be helpful here?

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