# 查看网络接口状态
ip link show
 
# 查看 IP 地址
ip addr show
 
# 测试网络连通性
ping -c 4 8.8.8.8
 
# 测试 DNS 解析
ping -c 4 www.baidu.com
 
# 检查 NetworkManager 状态
nmcli general status

# 查看以太网设备
lspci | grep -i ethernet
ip link show | grep -E "^[0-9]"
 
# 如果网卡未显示，检查驱动
sudo dmesg | grep -i eth
sudo dmesg | grep -i r8169  # Realtek 常见驱动

# 让 NetworkManager 重新申请地址（dhclient 已不再随系统提供）
sudo nmcli device reapply enp0s3
# systemd-networkd 环境下改用：
sudo networkctl renew enp0s3
 
# 或重新连接接口
sudo nmcli device connect enp0s3
 
# 手动配置静态 IP
sudo nmcli con mod "Wired connection 1" \
  ipv4.addresses 192.168.1.100/24 \
  ipv4.gateway 192.168.1.1 \
  ipv4.dns "8.8.8.8,114.114.114.114" \
  ipv4.method manual
sudo nmcli con up "Wired connection 1"

# 查看无线设备（iwconfig 已废弃，改用 iw）
iw dev
nmcli device wifi list
 
# 检查是否被射频开关禁用
rfkill list all
sudo rfkill unblock wifi

# 扫描可用网络
nmcli device wifi rescan
nmcli device wifi list
 
# 连接 Wi-Fi
nmcli device wifi connect "SSID名称" password "密码"
 
# 查看已保存的连接
nmcli connection show
 
# 删除有问题的连接重新添加
nmcli connection delete "连接名称"

# 检查电源管理是否关闭了 Wi-Fi
iw dev wlan0 get power_save
 
# 关闭 Wi-Fi 电源管理
sudo iw dev wlan0 set power_save off
 
# 永久生效
echo 'options iwlwifi power_save=0' | sudo tee /etc/modprobe.d/iwlwifi-powersave.conf

# 测试 DNS
nslookup www.baidu.com
dig www.baidu.com
 
# 查看当前 DNS 配置
resolvectl status
 
# 检查 systemd-resolved 状态
systemctl status systemd-resolved

# 临时修改（重启后失效）
sudo resolvectl dns enp0s3 8.8.8.8 114.114.114.114
 
# 通过 NetworkManager 永久修改
sudo nmcli con mod "连接名称" ipv4.dns "8.8.8.8 114.114.114.114"
sudo nmcli con mod "连接名称" ipv4.ignore-auto-dns yes
sudo nmcli con up "连接名称"

# 查看 UFW 状态
sudo ufw status verbose
 
# 临时关闭防火墙测试
sudo ufw disable
 
# 允许特定端口
sudo ufw allow 80/tcp
sudo ufw allow 443/tcp

# 设置环境变量
export http_proxy="http://127.0.0.1:7890"
export https_proxy="http://127.0.0.1:7890"
export no_proxy="localhost,127.0.0.1"
 
# 写入 ~/.bashrc 永久生效

sudo nano /etc/apt/apt.conf.d/proxy.conf

Acquire::http::Proxy "http://127.0.0.1:7890";
Acquire::https::Proxy "http://127.0.0.1:7890";

# 重启 NetworkManager
sudo systemctl restart NetworkManager
 
# 完全重置网络配置
sudo rm /etc/NetworkManager/system-connections/*
sudo systemctl restart NetworkManager