无法从外部本地网络连接到 C++ Linux 套接字程序

我有一个ubuntu linux服务器，它正在运行一个c++套接字程序，它应该在端口6555上侦听传入的连接，并向它们发送"欢迎到服务器!"当我从本地主机telnet时，它工作，但当我从外部网络telnet时，它不工作。

本地网络管理员告诉我，他已经将端口6555转发到服务器的本地IP，就像他之前为80所做的那样。

我也有一个web服务器在80端口上运行，我可以从任何地方telnet到它，所以我不知道问题是什么。

我尝试暂时禁用服务器上的iptables (ufw)防火墙并尝试连接，但没有区别。

打开端口检查器显示端口已关闭。这是否意味着转发没有工作?下面是用g++编译的代码:

#include <iostream>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <cstring>
#include <netinet/in.h>
#include <unistd.h>
#include "../include/netutils.hh"
int main() {
    sockaddr_storage clt_addr;
    socklen_t sin_size;
    int cltSock = -1;
    const std::string port = "6555";
    int servSock = -1;
    try {
        servSock = getSrvSocket(port, 10);
        while (true) {
            sin_size = sizeof clt_addr;
            cltSock = accept(servSock, (sockaddr*)&clt_addr, &sin_size);
            if (cltSock == -1) continue;
            if (!fork()) {
                close(servSock);
                send(cltSock, "Welcome to the server!n", 23, 0);
                while(true);
            }
            close(cltSock);
        }
    }
    catch(std::string excpt)
    {
        std::cerr << excpt << 'n';
        return -1;
    }
    return 0;
}

with getSrvSocket() in netutils.cc:

int getSrvSocket(std::string port, int BACKLOG) {
    int yes = 1;
    addrinfo *p;
    addrinfo hints;
    addrinfo *servinfo;
    memset(&hints, 0, sizeof hints);
    hints.ai_family = AF_UNSPEC;     //Can use either IPv4 or IPv6
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_flags = AI_PASSIVE;     //Automatically set IP address
    int sock = -1;
    if (getaddrinfo(NULL, port.c_str(), &hints, &servinfo) !=0) {
        throw std::string("Error: Could not resolve address info");
    }
    for (p = servinfo; p != NULL; p = p->ai_next) {
        sock = socket(p->ai_family, p->ai_socktype, p->ai_protocol);
        if (sock == -1) continue;
        if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &yes,
                    sizeof(int)) == -1) {
            throw std::string("Error: setsockopt() failure");
        }
        if (bind(sock, p->ai_addr, p->ai_addrlen) == -1) {
            close(sock);
            continue;
        }
        break;
    }
    freeaddrinfo(servinfo);
    if (NULL == p) throw std::string("Error: Server failed to bind");
    if (listen(sock, BACKLOG) == -1) {
        throw std::string("Error: Failed to to start listen()");
    }
    struct sigaction sa;
    sa.sa_handler = sigchld_handler;
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = SA_RESTART;
    if (sigaction(SIGCHLD, &sa, NULL) == -1) {
        throw std::string("Error: sigaction() failed");
    }
    return sock;
}