CentOS Dolphin网络配置详解

Note: “CentOS Dolphin” typically refers to CentOS 8/Stream 8 (or later) with the KDE Plasma Desktop Environment (where Dolphin is the default file manager). Network configuration in this context involves system-wide network settings (managed by NetworkManager) rather than Dolphin-specific configurations. Below is a detailed guide to system network configuration, which Dolphin relies on for network access.

1. Prerequisites

Ensure you have root privileges (or use sudo for commands).
Confirm the network interface name (e.g., ens33, eth0) using:
```
ip addr show
```
Look for interfaces with “UP” status (e.g., ens33).

2. Method 1: Using Command-Line Tools

2.1 View Current Network Configuration

Check interface details (IP, MAC, state):

ip addr show <interface>  # e.g., ip addr show ens33

Verify routing (gateway):
```
ip route show
```

Test connectivity:

ping 8.8.8.8  # Replace with a valid IP/hostname

2.2 Configure Static IP Address (Persistent)

Edit the interface configuration file (replace ens33 with your interface):
```
sudo vi /etc/sysconfig/network-scripts/ifcfg-ens33
```

Modify/Add these lines (adjust values to your network):

BOOTPROTO=static       # Disable DHCP
ONBOOT=yes             # Enable at boot
IPADDR=192.168.1.100   # Static IP
NETMASK=255.255.255.0  # Subnet mask (or use PREFIX=24)
GATEWAY=192.168.1.1    # Default gateway
DNS1=8.8.8.8           # Primary DNS
DNS2=8.8.4.4           # Secondary DNS

Save and exit (:wq in vi).

2.3 Restart Network Services

Apply changes using NetworkManager:
```
sudo systemctl restart NetworkManager
```

Verify the new configuration:

ip addr show ens33
ping www.google.com   # Test external connectivity

2.4 Configure DHCP (Automatic IP)

Edit the same file (ifcfg-ens33):

BOOTPROTO=dhcp         # Enable DHCP
ONBOOT=yes

Restart NetworkManager:
```
sudo systemctl restart NetworkManager
```

3. Method 2: Using Graphical Tools (nmtui)

For users preferring a GUI, nmtui (NetworkManager Text User Interface) is available:

Open the terminal and run:
```
sudo nmtui
```
Navigate to “Edit a connection” (use arrow keys) and select your interface (e.g., ens33).
Choose “Edit” and configure:
- IPv4 Configuration: Select “Manual”.
- Enter IP, Netmask (or Prefix), Gateway, and DNS servers.
Click “OK” to save, then “Back” to exit.
Restart the network service:
```
sudo systemctl restart NetworkManager
```

4. Method 3: Using nmcli (Command-Line Tool)

nmcli is a powerful CLI for NetworkManager:

List existing connections:
```
nmcli connection show
```
Edit the desired connection (replace ens33 with your connection name):
```
sudo nmcli connection edit ens33
```

Configure static IP:

set ipv4.addresses 192.168.1.100/24
set ipv4.gateway 192.168.1.1
set ipv4.dns "8.8.8.8,8.8.4.4"
set ipv4.method manual

Save and activate:
```
save
activate
```

Verify:

nmcli connection show ens33 | grep IPV4

5. Verify Network Connectivity

After any configuration change, use these commands:

Check interface IP:
```
ip addr show <interface>
```

Test local network:

ping 192.168.1.1  # Replace with your gateway

Test internet access:
```
ping www.google.com
```
Check DNS resolution:
```
nslookup google.com
```

6. Troubleshooting Common Issues

Interface not showing: Ensure the interface is enabled (ip link set <interface> up).
No IP assigned: Verify DHCP server availability or correct static IP settings.
Connection drops: Check cable integrity, router settings, or firewall rules (sudo firewall-cmd --list-all).
DNS resolution fails: Edit /etc/resolv.conf (add nameserver 8.8.8.8) or use nmcli to update DNS.

By following these steps, you can configure system-wide network settings for CentOS 8/Stream 8 (with KDE Plasma). Dolphin will automatically use these settings for network access.