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Ubuntu 服务器 22.04 如何从命令行确定正在使用哪个 DNS 服务器？

tag-icon • tag-icon networking command-line server 22.04 dns
Ubuntu 服务器 22.04 如何从命令行确定正在使用哪个 DNS 服务器？

我已经读过链接了这里。我从接受的答案中尝试了这个 nmcli device status ，但得到了这个结果 sudo: nmcli: command not found。然后我读了这链接。我尝试了这个 systemd-resolve --status | grep 'DNS Servers' ，但得到了这个结果 sudo: systemd-resolve: command not found。

有人知道可以在 22.04 上运行的命令吗？

答案1

在 Ubuntu Server 22.04 中，网络由 systemd-networkd（而不是 NetworkManager）管理。使用 Netplan 配置网络设置

DNS 名称解析由名为 systemd-resolved 的服务提供。它通过 D-Bus 接口、解析 NSS 服务 (nss-resolve(8)) 和 127.0.0.53 上的本地 DNS 存根侦听器提供 DNS 解析。如果您运行该命令，cat /etc/resolv.conf您会看到它将 127.0.0.53 列为 DNS 服务器。这是本地存根解析器。

$ cat /etc/resolv.conf
# This is /run/systemd/resolve/stub-resolv.conf managed by man:systemd-resolved(8).
# Do not edit.
#
# This file might be symlinked as /etc/resolv.conf. If you're looking at
# /etc/resolv.conf and seeing this text, you have followed the symlink.
#
# 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 should typically 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 localdomain

当您运行该命令时ls -l /etc/resolv.conf，您会看到它链接到定义本地存根解析器的文件：

$ ls -l /etc/resolv.conf
lrwxrwxrwx 1 root root 37 Mar 20 10:16 /etc/resolv.conf -> /run/systemd/resolve/stub-resolv.conf

这是正常行为。它会在本地缓存 DNS 查询以进行解析。如果查询不在缓存中，则它将查询通过 DHCP 提供或在 Netplan 配置文件中手动定义的任何上行 DNS 服务器。要查看您的上行 DNS 服务器，请运行resolvectl status：

$ resolvectl status
Global
       Protocols: -LLMNR -mDNS -DNSOverTLS
                  DNSSEC=no/unsupported
resolv.conf mode: stub

Link 2 (eth0)
Current Scopes: none
     Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS
                DNSSEC=no/unsupported

Link 3 (eth1)
Current Scopes: none
     Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS
                DNSSEC=no/unsupported

Link 4 (bond0)
    Current Scopes: DNS
         Protocols: +DefaultRoute +LLMNR -mDNS
                    -DNSOverTLS DNSSEC=no/unsupported
Current DNS Server: 192.168.10.1
       DNS Servers: 192.168.10.1
        DNS Domain: localdomain

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