There are several ways to view network card configuration in Linux system, which are described below.
- Method 1: ifconfig command to view and set the network card
- ifconfig: View all active network card information, you can view the IP address and subnet mask, but you cannot view the gateway and DNS address. You can also temporarily set the IP address and subnet mask of a certain network card.
[root@cloudgw ~]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.19.243.202 netmask 255.255.240.0 broadcast 172.19.255.255
ether 00:16:3e:04:2c:c4 txqueuelen 1000 (Ethernet)
RX packets 387660324 bytes 226790748853 (211.2 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 328446865 bytes 259013344959 (241.2 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
loop txqueuelen 1 (Local Loopback)
RX packets 249981451 bytes 195165066686 (181.7 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 249981451 bytes 195165066686 (181.7 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
eth0 is the first network card, lo represents the information of the local loopback network card.
- ifconfig -a: View all network card information, the result is as shown above.
- ifconfig eth0: View the information of the specific network card eth0
[root@cloudgw ~]# ifconfig eth0
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.19.243.202 netmask 255.255.240.0 broadcast 172.19.255.255
ether 00:16:3e:04:2c:c4 txqueuelen 1000 (Ethernet)
RX packets 387661202 bytes 226790872151 (211.2 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 328447665 bytes 259013675834 (241.2 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
- Method 2: View the network card information through the Linux network configuration file.
Enter the /etc/sysconfig/network-scripts/ path, you can see the file information of different network cards.
[root@cloudgw ~]# cd /etc/sysconfig/network-scripts/
[root@cloudgw network-scripts]# ll
total 224
-rw-r--r-- 1 root root 38 May 2 2018 ifcfg-eth0
-rw-r--r--. 1 root root 254 May 3 2017 ifcfg-lo
---
View the information of the first network card
[root@cloudgw network-scripts]# cat ifcfg-eth0
DEVICE=eth0
BOOTPROTO=dhcp
ONBOOT=yes
For more information, see the table below.
| Configuration | Description |
|---|---|
| DEVICE=eth0 | Network card device name, eth0 means the first network card |
| BOOTPROTO=none | Whether to automatically obtain IP (none, static, dhcp), when the value is dhcp, you only need to configure those items in the above example to connect to the Internet |
| HWADDR=00:0C:29:11:30:39 | MAC address |
| NM_CONTROLLED=yes | Can it be hosted by the Network Manager graphical management tool |
| ONBOOT=yes | Whether the current network card takes effect when the network service is started (ONBOOT is disabled by default in CentOS 6 and above) |
| TYPE=Ethernet | Network type, here is Ethernet |
| UUID=5ab36190-a5df-4bf1-94d8-6c126afd05f1 | Unique identification code |
| IPADDR=192.168.0.200 | IP address |
| NETMASK=255.255.255.0 | Subnet mask |
| GATEWAY=192.168.0.1 | Gateway |
| DNS1=202.106.0.20 | DNS |
| IPV6INIT=no | Whether IPv6 is enabled, here is set to not enable |
| USERCTL = no | Whether to allow non-root users to control this network card, here is not allowed |
Description:
- The condition for obtaining IP automatically is: There must be a DHCP server in the LAN.
- Computers with the same UUID network configuration will cause each other to be unable to access the Internet.