Question

操作系统是Ubuntu10.04。面板上的network connection图标显示有线网络连接处于活动状态，但我无法访问Internet。所以我手动设置了网络配置。我更改了/etc/resolv.conf，如下所示：

nameserver 202.112.14.151

202.112.14.151是我学校的DNS服务器的IP。 192.168.2.1是路由器的地址。我还更改了/etc/network/interfaces：

auto lo
iface lo inet loopback
auto eth0
iface eth0 inet static
address 192.168.2.107
netmask 255.255.255.0
gateway 192.168.2.1

/var/run/network/ifstate：

 lo=lo
 eth0=eth0

我的同学（我们在同一个房间并使用相同的路由器）使用

address:192.168.2.254
netmask:255.255.255.0
gateway:192.168.2.1   
DNS server:202.112.14.151

在Windows xp上配置网络可以访问Internet。我输入了命令ping 192.168.2.1，但它提醒我主机192.168.2.1无法访问。我是否疏忽了什么？请告诉我，Thx！

Answer 1

如果无法访问192.168.2.1，则您的局域网出现问题。这可能意味着您的适配器/电缆，但您说面板显示活动连接。您是否连接到交换机上的右侧交换机/右侧端口？您使用的是合适的电缆（尝试更换）吗？

尝试ping 192.168.2.255查看您是否可以访问网络上的任何节点。

Answer 2

这是解决方案 `public static void main（String [] args）{ 字符串IP;

    try {
        InetAddress ip = InetAddress.getLocalHost();
        IP=ip.getHostAddress();
        //Host NET ID
        System.out.println("Current IP address : " + IP);

        NetworkInterface network = NetworkInterface.getByInetAddress(ip);

        byte[] mac = network.getHardwareAddress();
        //Type
        System.out.println("Type Eth0/wlan     :"+network.getName());
        //SubNet Prefix
        System.out.println("SubNet ID :"+network.getInterfaceAddresses().get(0).getNetworkPrefixLength());
        System.out.println();
        //HostName
        System.out.println("HostName  :"+ip.getHostName());
        //MAC
        System.out.print("Current MAC address : ");
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < mac.length; i++) {
            sb.append(String.format("%02X%s", mac[i], (i < mac.length - 1) ? "-" : ""));        
        }
        System.out.println(sb.toString());

        InetAddress i = InetAddress.getLocalHost();
        byte[] ip1 = i.getAddress(); 
        for (int b = 0; b <255;b++) { 
            ip1[3] = (byte)b;
            InetAddress address = InetAddress.getByAddress(ip1); 
            if (address.isReachable(3000)) {
                System.out.println("\tIP :"+address.getHostAddress());
                NetworkInterface network1 = NetworkInterface.getByInetAddress(address);
                System.out.println("Type Eth0/wlan     :"+network.getName());
                System.out.println();
            } else if (!address.getHostAddress().equals(address.getHostName())) { 
                System.out.println("\tIP :"+address.getHostAddress());
            } else {
                System.out.println("NO");
            }
        }

    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}`

Output

有线网络连接处于活动状态，但无法连接到Internet

2 个答案: