Skip to content
Related Articles

Related Articles

Improve Article

C Program to display hostname and IP address

  • Difficulty Level : Medium
  • Last Updated : 24 Nov, 2017

There are many ways to find Hostname and IP address of a local machine. Here is a simple method to find hostname and IP address using C program.

We will be using the following functions :-

gethostname() : The gethostname function retrieves the standard host name for the local computer.

gethostbyname() : The gethostbyname function retrieves host information corresponding to a host name from a host database.

inet_ntoa() : The inet_ntoa function converts an (Ipv4) Internet network address into an ASCII string in Internet standard dotted-decimal format.


// C program to display hostname
// and IP address
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
// Returns hostname for the local computer
void checkHostName(int hostname)
    if (hostname == -1)
// Returns host information corresponding to host name
void checkHostEntry(struct hostent * hostentry)
    if (hostentry == NULL)
// Converts space-delimited IPv4 addresses
// to dotted-decimal format
void checkIPbuffer(char *IPbuffer)
    if (NULL == IPbuffer)
// Driver code
int main()
    char hostbuffer[256];
    char *IPbuffer;
    struct hostent *host_entry;
    int hostname;
    // To retrieve hostname
    hostname = gethostname(hostbuffer, sizeof(hostbuffer));
    // To retrieve host information
    host_entry = gethostbyname(hostbuffer);
    // To convert an Internet network
    // address into ASCII string
    IPbuffer = inet_ntoa(*((struct in_addr*)
    printf("Hostname: %s\n", hostbuffer);
    printf("Host IP: %s", IPbuffer);
    return 0;

Hostname: cContainer
Host IP:

Output varies machine to machine

Want to learn from the best curated videos and practice problems, check out the C Foundation Course for Basic to Advanced C.

My Personal Notes arrow_drop_up
Recommended Articles
Page :