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无法绑定到任何端口（Devuan）

tag-icon • tag-icon linux port-forwarding port
无法绑定到任何端口（Devuan）

我最近在建立 SSH 隧道时遇到了问题。事实证明，Apache 和 Nginx 都无法绑定到任何端口（即使以 root 身份和/或超出 <1024 范围）。来自这里我有一个小测试程序（就在下面）示例代码；我的版本输出如下），希望我能找到错误。但是，运行./server 6789和./client localhost 6789（在同一台机器上的两个终端中）没有出现错误。只是没有连接，所以server阻塞在accept()：

Server:
socket().
bzero().
htons().
bind().
listen().

Client:
socket().
gethostbyname().
bzero().
bcopy().
htons().
ERROR connecting: Connection timed out

输出语句是我的。它们是我唯一更改过的东西，在每次命令成功后打印出来。

Apache 和 Nginx 的行为类似，你只是无法连接到服务器。但是，使用 SSH 会出现错误：

$ ssh -4 -vvv -NL 5901:"$server":5901 "$user@$server"
[...]
debug1: Authentication succeeded (publickey).
Authenticated to <server> ([<ip>]:22).
debug1: Local connections to LOCALHOST:5901 forwarded to remote address <server>:5901
debug3: channel_setup_fwd_listener_tcpip: type 2 wildcard 0 addr NULL
debug1: Local forwarding listening on 127.0.0.1 port 5901.
bind: Cannot assign requested address
channel_setup_fwd_listener_tcpip: cannot listen to port: 5901
Could not request local forwarding.
debug2: fd 3 setting TCP_NODELAY
debug3: ssh_packet_set_tos: set IP_TOS 0x10
debug1: Requesting [email protected]

（如果没有-4，输出略有不同，但基本相同。）

Anki 的行为类似：

$ anki
Exception in thread Thread-1:
Traceback (most recent call last):
  File "threading.py", line 916, in _bootstrap_inner
  File "aqt/mediasrv.py", line 57, in run
  File "socketserver.py", line 453, in __init__
  File "aqt/mediasrv.py", line 38, in server_bind
  File "socketserver.py", line 467, in server_bind
OSError: [Errno 99] Cannot assign requested address

知道这里的问题是什么或我如何才能找出错误吗？

它已在 Devuan Jessie 上运行，在另一台运行 Devuan ASCII 的 PC 上也运行正常。我已经检查过其他安装中是否缺少某个包，但没有找到任何相关的东西（我有netbase）。

谢谢！

服务器.cpp：

/* A simple server in the internet domain using TCP
   The port number is passed as an argument */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h> 
#include <sys/socket.h>
#include <netinet/in.h>

void error(const char *msg)
{
    perror(msg);
    exit(1);
}

int main(int argc, char *argv[])
{
    puts("Server:");
    int sockfd, newsockfd, portno;
    socklen_t clilen;
    char buffer[256];
    struct sockaddr_in serv_addr, cli_addr;
    int n;
    if (argc < 2) {
        fprintf(stderr,"ERROR, no port provided\n");
        exit(1);
    }
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) 
        error("ERROR opening socket");
    puts("socket().");
    bzero((char *) &serv_addr, sizeof(serv_addr));
    puts("bzero().");
    portno = atoi(argv[1]);
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_addr.s_addr = INADDR_ANY;
    serv_addr.sin_port = htons(portno);
    puts("htons().");
    if (bind(sockfd, (struct sockaddr *) &serv_addr,
             sizeof(serv_addr)) < 0) 
        error("ERROR on binding");
    puts("bind().");
    listen(sockfd,5);
    puts("listen().");
    clilen = sizeof(cli_addr);
    newsockfd = accept(sockfd, 
                (struct sockaddr *) &cli_addr, 
                &clilen);
    if (newsockfd < 0) 
        error("ERROR on accept");
    puts("accept().");
    bzero(buffer,256);
    n = read(newsockfd,buffer,255);
    if (n < 0) error("ERROR reading from socket");
    printf("Here is the message: %s\n",buffer);
    n = write(newsockfd,"I got your message",18);
    if (n < 0) error("ERROR writing to socket");
    close(newsockfd);
    close(sockfd);
    return 0; 
}

客户端.cpp：

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h> 

void error(const char *msg)
{
    perror(msg);
    exit(0);
}

int main(int argc, char *argv[])
{
    puts("Client:");

    int sockfd, portno, n;
    struct sockaddr_in serv_addr;
    struct hostent *server;

    char buffer[256];
    if (argc < 3) {
       fprintf(stderr,"usage %s hostname port\n", argv[0]);
       exit(0);
    }
    portno = atoi(argv[2]);
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) 
        error("ERROR opening socket");
    puts("socket().");
    server = gethostbyname(argv[1]);
    if (server == NULL) {
        fprintf(stderr,"ERROR, no such host\n");
        exit(0);
    }
    puts("gethostbyname().");
    bzero((char *) &serv_addr, sizeof(serv_addr));
    puts("bzero().");
    serv_addr.sin_family = AF_INET;
    bcopy((char *)server->h_addr, 
         (char *)&serv_addr.sin_addr.s_addr,
         server->h_length);
    puts("bcopy().");
    serv_addr.sin_port = htons(portno);
    puts("htons().");
    if (connect(sockfd,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0) 
        error("ERROR connecting");
    printf("Please enter the message: ");
    bzero(buffer,256);
    fgets(buffer,255,stdin);
    n = write(sockfd,buffer,strlen(buffer));
    if (n < 0) 
         error("ERROR writing to socket");
    bzero(buffer,256);
    n = read(sockfd,buffer,255);
    if (n < 0) 
         error("ERROR reading from socket");
    printf("%s\n",buffer);
    close(sockfd);
    return 0;
}

答案1

输出ip addr show lo表明环回接口没有运行，因此可以快速修复

sudo ifup lo

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