一、配置步骤

1.确保 systemd-resolved 服务已启动

systemctl enable --now systemd-resolved
systemctl status systemd-resolved

2.配置 /etc/systemd/resolved.conf

vim /etc/systemd/resolved.conf

[Resolve]
# DNS 按优先级从左到右排列（左侧为主，右侧依次为备用）
DNS=114.114.114.114 223.5.5.5
# 主 DNS 已经够用，Fallback 可以留空，或者写一个可靠的国内备用
FallbackDNS=
# DNSSEC 安全模式：no, yes, allow-downgrade 尝试验证签名，若上游 DNS 不支持或校验失败则自动降级为普通查询，设为 "yes" 强校验可能导致国内部分网站解析失败，建议保持 allow-downgrade
DNSSEC=allow-downgrade

# DNS 解析服务进程
systemctl restart systemd-resolved

3.将 /etc/resolv.conf 改为指向 systemd-resolved 的动态文件

mv /etc/resolv.conf /etc/resolv.conf.bak
ln -s /run/systemd/resolve/resolv.conf /etc/resolv.conf

4.防止 dhclient 删除或覆盖这个软链接

vim /etc/sysconfig/network-scripts/ifcfg-enp3s0

# 禁止 dhclient 修改 resolv.conf
PEERDNS=no

5.重启网络

systemctl restart network

# 查看 DNS 解析器配置
cat /etc/resolv.conf