CentOS Dolphin网络配置技巧

Note: “CentOS Dolphin” typically refers to CentOS 8/Stream 8 (or later) with the KDE Plasma Desktop (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 are key network configuration techniques for CentOS with KDE Dolphin:

1. View Current Network Configuration

Before making changes, verify existing network interfaces and settings:

Command Line: Use ip addr show (preferred) or ifconfig (legacy) to list all network interfaces, their IP addresses, and statuses.
```
ip addr show
```
GUI: Click the network icon in the KDE Plasma taskbar → Select “Connection Information” to view interface details.

2. Configure Static IP Address (Command Line)

For a persistent static IP setup (recommended for servers or fixed networks):

Edit the network interface configuration file (replace ens33 with your actual interface name, e.g., eth0):
```
sudo vi /etc/sysconfig/network-scripts/ifcfg-ens33
```

Modify the following parameters (adjust values to match your network):

BOOTPROTO=static       # Disable DHCP (use static IP)
ONBOOT=yes             # Enable interface at boot
IPADDR=192.168.1.100   # Static IP address
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 server
DNS2=8.8.4.4           # Secondary DNS server

Save the file and restart the network service:
```
sudo systemctl restart NetworkManager
```

Verify connectivity:

ip addr show ens33     # Check IP assignment
ping 8.8.8.8           # Test external connectivity

3. Configure Static IP Address (GUI via nmtui)

For a user-friendly approach, use the NetworkManager Text User Interface (nmtui):

Open nmtui in the terminal:
```
sudo nmtui
```
Navigate to “Edit a connection” → Select your interface (e.g., ens33) → Press Enter.
Switch to the “IPv4 Configuration” section:
- Set Method to “Manual”.
- Add IP addresses (e.g., 192.168.1.100/24), gateway (192.168.1.1), and DNS servers (comma-separated).
Press Tab to highlight OK → Press Enter → Save changes.
Restart the network service to apply:
```
sudo systemctl restart NetworkManager
```

4. Configure Static IP Address (GUI via System Settings)

Alternatively, use the KDE Plasma System Settings for network configuration:

Click the application menu → Select “System Settings” → “Connections”.
Select your network interface (e.g., “Wired Connection 1”) → Click Edit.
Go to the IPv4 tab:
- Set Method to “Manual”.
- Enter IP address, netmask (or prefix), gateway, and DNS servers.
Click Apply → Restart the network service if prompted.

5. Configure Network Proxy (for Dolphin/KDE)

If your network requires a proxy server (e.g., for internet access in Dolphin):

Open System Settings → “Network” → “Proxy”.
Select Manual proxy configuration → Enter:
- HTTP Proxy: proxy.example.com (replace with your proxy address)
- Port: 8080 (default for HTTP proxies)
Optionally, configure proxy exceptions (e.g., localhost, 127.0.0.1).
Click Apply → Restart Dolphin to apply proxy settings.

6. Troubleshooting Common Issues

Interface Not Showing Up: Ensure the interface is enabled (ONBOOT=yes in config file) and cables are connected. Use ip link show to check interface status.
No Internet Access: Verify gateway/DNS settings. Test connectivity with ping 192.168.1.1 (gateway) and ping 8.8.8.8 (external DNS).
Configuration Not Applied: Restart NetworkManager (sudo systemctl restart NetworkManager) instead of the legacy network service.
Firewall Blocking Traffic: Temporarily disable the firewall to test (sudo systemctl stop firewalld)—re-enable it afterward for security.

These techniques cover essential network configuration tasks for CentOS with KDE Dolphin. For advanced scenarios (e.g., VLANs, bonding), refer to the CentOS NetworkManager documentation.