Unix - how to get IP address of domain name?

Jake picture Jake · May 1, 2012 · Viewed 18.1k times · Source

In a C program in UNIX, gethostbyname() can be used to obtain the address of domain like "localhost". How does one convert the result from gethostbyname() to dotted decimal notation.

struct hostent* pHostInfo;
long nHostAddress;

/* get IP address from name */
pHostInfo=gethostbyname("localhost");

if(!pHostInfo){
    printf("Could not resolve host name\n");
    return 0;
}

/* copy address into long */
memset(&nHostAddress, 0, sizeof(nHostAddress));
memcpy(&nHostAddress,pHostInfo->h_addr,pHostInfo->h_length);

nHostAddress contains the following:

16777243

How do I convert the result so that I can get the output as :

127.0.0.1

Answer

Mohit Dabas picture Mohit Dabas · Jun 2, 2015

It is easy Just Compile This Code

#include<stdio.h>
#include<netdb.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
int main()
{
    struct hostent *ghbn=gethostbyname("www.kamonesium.in");//change the domain name
    if (ghbn) {
        printf("Host Name->%s\n", ghbn->h_name);
        printf("IP ADDRESS->%s\n",inet_ntoa(*(struct in_addr *)ghbn->h_name) );
    }
}