Learn How to Set IP using Linux and C: The Ultimate Guide（linuxc设置ip）

Studying how to configure IP addresses or network interfaces using Linux can be a bewildering task at first. But with a bit of guidance, few commands, and a few snippets of C, you can become comfortable with configuring IP settings on Linux. This article will provide comprehensive information on how to set the IP in both Linux and C and provide answers to commonly asked questions about IP settings.

It’s essential to know how to customize some of the more advanced IP settings in order to securely remote access a Linux machine from the outside world. After reading this article, you’ll have a sound understanding of the following IP settings topics:

-What is IP?

-How to set up IP in Linux

-How to assign an IP address in C

What is IP?

IP (Internet Protocol) is a way for data to be routed across networks, like the internet. It requires that each machine connected to the IP network has an associated IP address. This IP address will be used to send and receive data, ensuring communication is sent securely.

How to set up IP in Linux

To start, you’ll first need to identify the network interface you would like to change the IP address of. This can be done by running the “ip addr” command, which will print out a list of all the network interfaces connected to your Linux machine.

Once you’ve identified the interface you would like to modify, run the following command as root user:

ifconfig eth0 netmask

This command will set the IP address of the mentioned interface to the specified IP address and netmask. For example, entering

ifconfig eth0 192.168.0.3 netmask 255.255.255.0

will set the IP address of eth0 to 192.168.0.3 and the netmask to 255.255.255.0.

How to assign an IP address in C

When configuring IP addresses or network interfaces using C, you’ll need to create a program that needs to communicate with the operating system. The program can then request information regarding IP settings or send commands to modify the IP settings.

For example, the following code can be used to request the system’s current IP settings:

#include

#include

#include

#include

#include

int main(){

char hostname[256];

struct hostent *hostInfo;

struct in_addr ipAddress;

memset(hostname, 0x00, 256);

gethostname(hostname, 255);

hostInfo = gethostbyname(hostname);

memcpy(&ipAddress, hostInfo->h_addr_list[0], hostInfo->h_length);

printf(“IP address of %s is %s\n”, hostname, inet_ntoa(ipAddress));

return 0;

}

The program can also be used to set an IP address manually. To do so, use the setsockopt() command followed by the SO_BINDTODEVICE flag. The flag needs to be set to the desired network interface, like eth0, and the IP address should be set using the sockaddr_in data structure.

In conclusion, setting an IP address is an essential task for managing a Linux machine or C program. It is recommended to understand the basics of IP settings before attempting to make more advanced changes to the system. This article provided comprehensive information on how to set IP in Linux and C by providing sample commands and code snippets.