c/c++语言实现连接pop3服务器

[玩命速递]

只要实现连接就可以了，连接成功就显示“连接成功”，用户名或密码错就显示“连接失败”，不需要显示邮箱的邮件总数、大小等详细信息。感激。

[景语]

POP3的端口号是110
网易邮箱pop3.163.com的IP是220.181.12.101

用socket连接这个套接字

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/stat.h>

#define SERVPORT 110
#define MAX 4096

int main(int argc, char *argv[]) {
         int sockfd, sendBytes, recvBytes;
	char choice;
	char buf[MAX];
	struct hostent *host;
	struct sockaddr_in servSockaddr;

	if(argc != 2) {
		fprintf(stderr,"usage:./client [hostname]\n");
		//exit(1);
	}

	/*translate the address*/
	if((host = gethostbyname(argv[1])) == NULL) {
		perror("fail to get host by name\n");
		exit(1);
	}

	/*establish a socket*/
	if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
		perror("fail to establish a socket\n");
		exit(1);
	}
	
	/*init serverSockaddr*/
	servSockaddr.sin_family = AF_INET;
	servSockaddr.sin_port = htons(SERVPORT);
	servSockaddr.sin_addr = *((struct in_addr *)host -> h_addr);
	bzero(&(servSockaddr.sin_zero), 8);

	/*connect the server*/
	if(connect(sockfd, (struct sockaddr *)&servSockaddr, sizeof(struct sockaddr_in)) == -1) {
		perror("fail to connect the socket\n");
		exit(1);
	}
	printf("Success to connect the server!\n");
	printf("Welcome to join %s!\n", inet_ntoa(servSockaddr.sin_addr));
}

编译运行
jimmy@MyPet:~/code/ftp/client$ make
gcc -ggdb3 ftpcli.c -o ftpcli

jimmy@MyPet:~/code/ftp/client$ ./ftpcli pop3.163.com
Success to connect the server!
Welcome to join 220.181.12.101!

[玩命速递]

感谢 jmy5945hh 大神，