# include unistd.h
# include sys/socket.h
# include sys/types.h
# include string.h
# include netinet/in.h
# include stdio.h
# include stdlib.h
#include netinet/ip.h
#include netinet/ip_icmp.h
int main(){
int sockfd,retval,n;
socklen_t clilen; //소켓 길이 , 크기
struct sockaddr_in cliaddr, servaddr; // 소켓 주소 , 서버 주소
char buf[10000];
int i;
