In Linux systems, there are many commonly used network commands that can be used for network configuration and troubleshooting. These commands can help us understand the status and performance of the network, and can quickly diagnose and solve network problems. In this article, we will introduce some commonly used Linux network commands and provide some cases to help you better understand their usage.
1、ping
The ping command is used to test the connection with the target host. It sends an ICMP echo request to the target host and waits for its response. If the target host is functioning and connected, you will receive an echo response. If you do not receive a response, there is a problem and further troubleshooting is required.
For example, if you want to test the connection to the host 192.168.1.1, you can use the following command:
ping 192.168.1.1
2、traceroute
The traceroute command is used to trace the path of packets from the local host to the destination host. It sends a series of UDP packets to the target host, and records the routers that each packet passes through. This way, you can see on which routers the packets are having problems and troubleshoot accordingly.
For example, if you want to trace the path to the host 192.168.1.1, you can use the following command:
traceroute 192.168.1.1
3、netstat
The netstat command is used to display the current network connection status of the system. It can display all network connections, including TCP, UDP and UNIX domain sockets. By viewing the status of your network connections, you can see which services are running and which services are consuming network bandwidth.
For example, if you want to see all network connections of the current system, you can use the following command:
netstat -a
4、nslookup
The nslookup command is used to query a DNS server for hostname or IP address information. It can help you understand the mapping relationship between hostnames and IP addresses, and diagnose problems with DNS servers.
For example, if you want to query the IP address of the host www.example.com, you can use the following command:
nslookup www.example.com
5、ifconfig
The ifconfig command is used to configure and display the status of network interfaces. It can display all network interfaces in the current system, and can be used to configure network parameters such as IP address, subnet mask, and gateway.
For example, if you want to display all network interfaces on the current system, you can use the following command:
ifconfig -a
6、iptables
The iptables command is used to configure firewall rules in Linux systems. It can be used to limit the network traffic entering and leaving the system and can protect the system from cyber attacks.
For example, if you want to allow ICMP traffic from the 192.168.1.0/24 network, you can use the following command:
iptables -A INPUT -s 192.168.1.0/24 -p icmp -j ACCEPT
The above are some commonly used Linux network commands and their usage. By using these commands, you can gain a better understanding of your system's network status and performance, and quickly diagnose and resolve network problems.
the case
The following is a case that demonstrates how to use the ping command to test the connection with the target host.
Let's say you want to test the connection to the host 192.168.1.1. You can use the following command:
ping 192.168.1.1
If the connection is OK, output similar to the following is displayed:
PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data.
64 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=0.259 ms
64 bytes from 192.168.1.1: icmp_seq=2 ttl=64 time=0.265 ms
64 bytes from 192.168.1.1: icmp_seq=3 ttl=64 time=0.247 ms
64 bytes from 192.168.1.1: icmp_seq=4 ttl=64 time=0.264 ms
Among them, the first line displays the IP address of the host being pinged, and the second line begins to display the echo response information. If the connection is not working, output similar to the following is displayed:
PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data.
From 192.168.1.2 icmp_seq=1 Destination Host Unreachable
From 192.168.1.2 icmp_seq=2 Destination Host Unreachable
From 192.168.1.2 icmp_seq=3 Destination Host Unreachable
Among them, the first line shows the IP address of the host being pinged, and the following lines show the connection failure information. In this case, you need to troubleshoot further, such as checking that the network connection is fine, or checking that the target host is down.
Summarize
In short, the above are some commonly used Linux network commands and their usage. By proficiency in these commands, you can better understand the network status and performance of the system, and quickly diagnose and solve network problems.