編輯 (tl;dr)
我似乎已经发现了问题的一部分这里/etc/resolv.conf，因为至少和相关文件的差异已经消失了。
但我仍然无法通过 WiFi 连接，因此其他差异可能仍然存在。
我想要识别这些并采取行动。
我特意选择了与这个 OP。我有两个 Ubuntu 系统，server1和server2，各方面都非常相似。两者都通过 WiFi 连接到同一个路由器。我通过比较这两个系统来帮助追踪问题。
在server2，我刚开始遇到 DNS 名称解析问题。我连接到 VPN，服务器重新启动了，所以我猜这后记可能描述了这种情况。
server2没有resolvconf，我安装了它作为结果。当时/etc/resolv.conf开始指向/run/resolvconf/resolv.conf（注意下面的修改日期），而不是/run/systemd/resolve/stub-resolv.conf。要做到这一点，我必须手动添加在 顶部输入 nameserver 8.8.8.8 /etc/resolv.conf，插入有线互联网连接，我就可以立即sudo apt update等。注意：截至目前，上述链接中引用的文件权限问题不存在。如果下次我连接/断开 VPN 时出现此问题，我会处理它。
我列出如下：1）有什么不同吗在server1和中server2，2）有什么相同之处（替换any服务器名称），以及 3）几乎一样（据我理解，存在无关的差异）。
为什么DIFFERENCE #3在下面？（nameserver ::1）。
如果可能的话，如何修复server2，通过保留与相同的配置server1？
我可以试试修改/etc/resolvconf/resolv.conf.d/tail，server2但由于该文件为空，server1此操作即使成功也可能会掩盖其他问题。
我想如果我能修复下面的差异 #1-4，问题就会解决。但所有 4 个文件都被视为动态创建的。我找不到谁是/负责“创建”差异的，以及如何修复它。
不同的
dig：
[server1]$ dig google.com
; <<>> DiG 9.16.1-Ubuntu <<>> google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 64202
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;google.com. IN A
;; ANSWER SECTION:
google.com. 94 IN A 216.58.202.46
;; Query time: 36 msec
;; SERVER: 127.0.0.53#53(127.0.0.53)
;; WHEN: mar ago 10 03:44:51 -03 2021
;; MSG SIZE rcvd: 55
对阵
[server2]$ dig google.com
; <<>> DiG 9.16.1-Ubuntu <<>> google.com
;; global options: +cmd
;; connection timed out; no servers could be reached
/etc/resolv.conf及相关文件：
[server1]$ cat /etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
# 127.0.0.53 is the systemd-resolved stub resolver.
# run "systemd-resolve --status" to see details about the actual nameservers.
nameserver 127.0.0.53
search fibertel.com.ar <--- DIFFERENCE #1
[server1]$ cat /run/systemd/resolve/stub-resolv.conf
# This file is managed by man:systemd-resolved(8). Do not edit.
#
# This is a dynamic resolv.conf file for connecting local clients to the
# internal DNS stub resolver of systemd-resolved. This file lists all
# configured search domains.
#
# Run "resolvectl status" to see details about the uplink DNS servers
# currently in use.
#
# Third party programs must not access this file directly, but only through the
# symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a different way,
# replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.
nameserver 127.0.0.53
options edns0 trust-ad
search fibertel.com.ar <--- DIFFERENCE #2
[server1]$ cat /run/systemd/resolve/resolv.conf
# This file is managed by man:systemd-resolved(8). Do not edit.
#
# This is a dynamic resolv.conf file for connecting local clients directly to
# all known uplink DNS servers. This file lists all configured search domains.
#
# Third party programs must not access this file directly, but only through the
# symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a different way,
# replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.
nameserver 192.168.0.1 <--- DIFFERENCE #3
search fibertel.com.ar <--- DIFFERENCE #3
[server1]$ cat /run/resolvconf/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
# 127.0.0.53 is the systemd-resolved stub resolver.
# run "systemd-resolve --status" to see details about the actual nameservers.
nameserver 127.0.0.53
search fibertel.com.ar <--- DIFFERENCE #4
[server1]$ ll /etc/resolv.conf
lrwxrwxrwx 1 root root 29 feb 1 2021 /etc/resolv.conf -> ../run/resolvconf/resolv.conf
[server1]$ ll /run/resolvconf/resolv.conf
-rw-r--r-- 1 root root 327 ago 9 20:59 /run/resolvconf/resolv.conf
对阵
[server2]$ cat /etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
# 127.0.0.53 is the systemd-resolved stub resolver.
# run "systemd-resolve --status" to see details about the actual nameservers.
nameserver 127.0.0.53
[server2]$ cat /run/systemd/resolve/stub-resolv.conf
# This file is managed by man:systemd-resolved(8). Do not edit.
#
# This is a dynamic resolv.conf file for connecting local clients to the
# internal DNS stub resolver of systemd-resolved. This file lists all
# configured search domains.
#
# Run "resolvectl status" to see details about the uplink DNS servers
# currently in use.
#
# Third party programs must not access this file directly, but only through the
# symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a different way,
# replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.
nameserver 127.0.0.53
options edns0 trust-ad
[server2]$ cat /run/systemd/resolve/resolv.conf
# This file is managed by man:systemd-resolved(8). Do not edit.
#
# This is a dynamic resolv.conf file for connecting local clients directly to
# all known uplink DNS servers. This file lists all configured search domains.
#
# Third party programs must not access this file directly, but only through the
# symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a different way,
# replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.
nameserver ::1 <--- DIFFERENCE #3
[server2]$ cat /run/resolvconf/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
# 127.0.0.53 is the systemd-resolved stub resolver.
# run "systemd-resolve --status" to see details about the actual nameservers.
nameserver 127.0.0.53
[server2]$ ll /etc/resolv.conf
lrwxrwxrwx 1 root root 29 ago 9 22:38 /etc/resolv.conf -> ../run/resolvconf/resolv.conf
[server2]$ ll /run/resolvconf/resolv.conf
-rw-r--r-- 1 root root 304 ago 10 03:13 /run/resolvconf/resolv.conf
相同的
[any]$ uname -a
Linux <serverN> 5.11.0-25-generic #27~20.04.1-Ubuntu SMP Tue Jul 13 17:41:23 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
[any]$ dpkg -l | grep resolvconf
ii resolvconf 1.82 all name server information handler
[any]$ cat /etc/netplan/01-network-manager-all.yaml
# Let NetworkManager manage all devices on this system
network:
version: 2
renderer: NetworkManager
[any]$ cat /etc/NetworkManager/NetworkManager.conf
[main]
plugins=ifupdown,keyfile
[ifupdown]
managed=false
[device]
wifi.scan-rand-mac-address=no
[any]$ cat /etc/hosts
127.0.0.1 localhost
127.0.1.1 <serverN>
# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
[any]$ cat /etc/nsswitch.conf
...
[any]$ cat /etc/systemd/networkd.conf
...
[any]$ ss -plnt | grep ':53'
LISTEN 0 4096 127.0.0.53%lo:53 0.0.0.0:*
[any]$ sudo systemctl status resolvconf.service
...
[any]$ /lib/systemd/network/
...
差不多一样
[server1]$ lsb_release -a
LSB Version: core-11.1.0ubuntu2-noarch:security-11.1.0ubuntu2-noarch
Distributor ID: Ubuntu
Description: Ubuntu 20.04.2 LTS
Release: 20.04
Codename: focal
[server2]$ lsb_release -a
LSB Version: core-11.1.0ubuntu2-noarch:printing-11.1.0ubuntu2-noarch:security-11.1.0ubuntu2-noarch
Distributor ID: Ubuntu
Description: Ubuntu 20.04.2 LTS
Release: 20.04
Codename: focal
有关的：
答案1
文件 /etc/resolv.conf 旨在作为 /run/systemd/resolve/stub-resolv.conf 的符号链接，请检查：
ls -al /etc/resolv.conf
如果不是，请更正：
sudo rm /etc/resolv.conf
sudo ln -s /run/systemd/resolve/stub-resolv.conf /etc/resolv.conf
您的 netplan yaml 文件表明您正在运行网络管理器。这是对 DNS 名称服务器进行更改的地方。
