Socket编程connection refused问题

[景语]

学习socket，自己试着编了一个C/S程序
代码如下：

/*
 *
 * client
 *
 * */
#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>
#define SERVPORT 1234
#define MAXDATASIZE 100
int main(int argc, char *argv[]) {
    int sockfd, sendBytes;
    char buf[MAXDATASIZE];
    struct hostent *host;
    struct sockaddr_in servAddr;
    if(argc != 2) {
        fprintf(stderr,"usage:./client [hostname]");
        exit(1);
    }
    /*translate the address*/
    if((host = gethostbyname(argv[1])) == NULL) {
        perror("fail to get host by name");
        exit(1);
    }
    printf("Success to get host by name...\n");
    /*establish a socket*/
    if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        perror("fail to establish a socket");
        exit(1);
    }
    printf("Success to establish a socket...\n");
   
    /*init sockaddr_in*/
    servAddr.sin_family = AF_INET;
    servAddr.sin_port = SERVPORT;
    servAddr.sin_addr = *((struct in_addr *)host -> h_addr);
    bzero(&(servAddr.sin_zero), 8);
    /*connect the socket*/
    if(connect(sockfd, (struct sockaddr *)&servAddr, sizeof(struct sockaddr)) == -1) {
        perror("fail to connect the socket");
        exit(1);
    }
    printf("Success to connect the socket...\b");
    /*send datas to server*/
    if(sendBytes = send(sockfd, "hello", 5, 0) == -1) {
        perror("fail to send datas");
        exit(1);
    }
    printf("Success to send data!");
    close(sockfd);
}

    /*
     *
     * server
     *
     * */
    #include<stdio.h>
    #include<stdlib.h>
    #include<errno.h>
    #include<string.h>
    #include<netdb.h>
    #include<unistd.h>
    #include<sys/types.h>
    #include<sys/types.h>
    #include<sys/socket.h>
    #include<netinet/in.h>
    #define SERVPORT 1234
    #define BACKLOG 20
    #define MAX_CON_NO 10
    #define MAX_DATA_SIZE 5
    int main() {
        struct sockaddr_in serverSockaddr, clientSockaddr;
        int sinSize, recvBytes;
        int sockfd, clientfd;
        char buf[MAX_DATA_SIZE];
        /*establish a socket*/
        if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
            perror("fail to establish a socket");
            exit(1);
        }
        printf("Success to establish a socket...(sockfd = %d)\n", sockfd);
        /*init sockaddr_in*/
        serverSockaddr.sin_family = AF_INET;
        serverSockaddr.sin_port = htons(SERVPORT);
        serverSockaddr.sin_addr.s_addr = INADDR_ANY;
        bzero(&(serverSockaddr.sin_zero), 8);
        /*bind socket*/
        if(bind(sockfd, (struct sockaddr *)&serverSockaddr, sizeof(struct sockaddr))== -1) {
            perror("fail to bind");
            exit(1);
        }
        printf("Success to bind the socket...\n");
        /*listen on the socket*/
        if(listen(sockfd, BACKLOG) == -1) {
            perror("fail to listen");
            exit(1);
        }
        printf("Success to listen on the socket...\n");
        /*accept a client's request*/
        if((clientfd = accept(sockfd, (struct sockaddr *)&clientSockaddr, &sinSize)) == -1) {
            perror("fail to acceot");
            exit(1);
        }
        printf("Success to accpet...\n");
        /*call recv to receive datas*/
        if((recvBytes = recv(sockfd, buf, MAX_DATA_SIZE, 0)) == -1) {
                perror("fail to receive datas");
                exit(1);
        }
        printf("Receive a connection:%s \n", buf);
        close(sockfd);
    }

在UBUNTU防火墙关闭情况下终端1执行

    jimmy@MyPet:~$ gcc -o server server.c
    jimmy@MyPet:~$ gcc -o client client.c
    jimmy@MyPet:~$ ./server
    Success to establish a socket...(sockfd = 3)
    Success to bind the socket...
    Success to listen on the socket...

终端2执行

    jimmy@MyPet:~$ ./client MyPet
    Success to get host by name...
    Success to establish a socket...
    fail to connect the socket: Connection refused
    jimmy@MyPet:~$ ./client 127.0.0.1
    Success to get host by name...
    Success to establish a socket...
    fail to connect the socket: Connection refused
    jimmy@MyPet:~$ ./client 127.0.1.1
    Success to get host by name...
    Success to establish a socket...
    fail to connect the socket: Connection refused
    jimmy@MyPet:~$ 

查看端口

    jimmy@MyPet:~$ nmap MyPet
    Starting Nmap 5.21 ( http://nmap.org ) at 2012-02-19 14:35 CST
    Nmap scan report for MyPet (127.0.1.1)
    Host is up (0.00043s latency).
    Not shown: 998 closed ports
    PORT     STATE SERVICE
    21/tcp   open  ftp
    1234/tcp open  hotline
    Nmap done: 1 IP address (1 host up) scanned in 0.19 seconds

请问众位大神这client端运行时的connection refused是怎么回事呢？服务器的问题吗？
但是根据端口情况应该是在进行监听的。

谢谢！

[qq120848369]

netstat -tanlp 看看你的服务端处于什么状态, 是listen还是time_wait.

错误原因是因为服务端bind失败, socket创建之后, int on = 1; setsockopt(SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); bind();listen();

[景语]

[Quote=引用 1 楼 qq120848369 的回复:]

C/C++ code
netstat -tanlp 看看你的服务端处于什么状态, 是listen还是time_wait.

错误原因是因为服务端bind失败, socket创建之后, int on = 1; setsockopt(SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); bind();listen();
[/Quote]

这是服务端状态结果

jimmy@MyPet:~$ netstat -tanlp 127.0.1.1
(Not all processes could be identified, non-owned process info
 will not be shown, you would have to be root to see it all.)
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 0.0.0.0:1234            0.0.0.0:*               LISTEN      2485/server

另外我在socket()与bind()之间加入了你说的代码

int on = 1; 
setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));

重新编译运行后依然提示为connection refused

[qq120848369]

客户端的PORT没做htons

[qq120848369]

if(connect(sockfd, (struct sockaddr *)&servAddr, sizeof(struct sockaddr)) == -1) {

第三个参数用sizoef(struct sockaddr_in)

[景语]

[Quote=引用 3 楼 qq120848369 的回复:]

客户端的PORT没做htons
[/Quote]

解决了，非常感谢！