No route to host 에러가 납니다.

#include <stdio.h>
#include <netdb.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
 
#define PORT 12345
#define MAX 80
 
/* Function designed for chat between client and server */
void func(int sockfd)
{
   char buff[MAX];
   int n;
 
   for (;;)
   {
      bzero(buff, MAX);
 
      /* read the message from client and copy it in buffer */
      read(sockfd, buff, sizeof(buff));
 
      /* print buffer which contains the client contents */
      printf("From client : %s\t To client : ", buff);
 
      bzero(buff, MAX);
      n = 0;
 
      /* copy server message in the buffer */
      while ((buff[n++] = getchar()) != '\n')
         ;
 
      /* and send that buffer to client */
      write(sockfd, buff, sizeof(buff));
 
      /* if msg contains "Exit" then server exit and chat ended */
      if (strncmp("exit", buff, 4) == 0)
      {
         printf("Server Exit ....\n");
         break;
      }
   }
}
 
 
int main()
{
   int sockfd, connfd, len;
   struct sockaddr_in servaddr, cli;
 
   /* socket creation and verification */
   sockfd = socket(AF_INET, SOCK_STREAM, 0);
   if (sockfd == -1)
   {
      printf("socket creation failed...\n");
      exit(0);
   }
   else
   {
      printf("socket successfully created...\n");
   }
 
   bzero(&servaddr, sizeof(servaddr));
 
   /* assign IP and PORT */
   servaddr.sin_family = AF_INET;
   servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
   servaddr.sin_port = htons(PORT);
 
   if ((bind(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr))) != 0)
   {
      printf("socket bind failed...\n");
      exit(0);
   }
   else
   {
      printf("Socket successfully binded...\n");
   }
 
   /* Now server is ready to listen and verification */
   if ((listen(sockfd, 5)) != 0)
   {
      printf("Listen failed ...\n");
      exit(0);
   }
   else
   {
      printf("Server listening ...\n");
   }
 
   len = sizeof(cli);
 
 
   /* Accept the data packet from client and verification */
   connfd = accept(sockfd, (struct sockaddr *)&cli, &len);
   if (connfd < 0)
   {
      printf("Server accept failed...\n");
      exit(0);
   }
   else
   {
      printf("Server accept the client...\n");
   }
 
   /* Function for chatting between client and server */
   func(connfd);
 
   /* After chatting, close the socket */
   close(sockfd);
}

#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <unistd.h>
 
#define MAX 80
#define PORT 12345
 
void func(int sockfd)
{
   char buff[MAX];
   int n;
 
   for (;;)
   {
      bzero(buff, sizeof(buff));
      printf("Enter the string : ");
 
      n = 0;
      while ((buff[n++] = getchar()) != '\n')
         ;
 
      write(sockfd, buff, sizeof(buff));
      bzero(buff, sizeof(buff));
 
      read(sockfd, buff, sizeof(buff));
      printf("From Server : %s", buff);
 
      if ((strncmp(buff, "exit", 4)) == 0)
      {
         printf("Client Exit ...\n");
         break;
      }
   }
}
 
 
int main()
{
   int sockfd, connfd;
   struct sockaddr_in servaddr, cli;
 
   /* socket create and verification */
   sockfd = socket(AF_INET, SOCK_STREAM, 0);
   if (sockfd == -1)
   {
      printf("socket creation failed...\n");
      exit(0);
   }
   else
   {
      printf("socket successfully created...\n");
   }
 
   bzero(&servaddr, sizeof(servaddr));
 
   /* assign IP, PORT */
   servaddr.sin_family = AF_INET;
   servaddr.sin_addr.s_addr = inet_addr("192.168.1.203");
   servaddr.sin_port = htons(PORT);
 
   /* connect the client socket to server socket */
   if (connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) != 0)
   {
      printf("connection with the server failed ...\n");
      printf("error : %s\n", strerror(errno));
      exit(0);
   }
   else
   {
      printf("connected to the server ...\n");
   }
 
   /* function for chat */
   func(sockfd);
 
   /* close the socket */
   close(sockfd);
   return 0;
}