我的 c/s 程序在局域网测试一切正常，但到了互联网，客户端无法与服务器建立连接，帮我看看啊

已知服务器有真实网上IP
======================================================================
服务端连接：m_Serv.sin_addr.s_addr=htonl(INADDR_ANY);
m_Serv.sin_family=AF_INET;
m_Serv.sin_port=5000;
m_AddLen=sizeof(m_Serv);
//创建Socket
m_Sock=socket(AF_INET,SOCK_STREAM,0);
//绑定
if (bind(m_Sock,(sockaddr*)&m_Serv,m_AddLen))
{
    m_strOutput=_T("绑定错误");
}
else
{
    m_strOutput=_T("服务器准备就绪");
    //开始侦听
    listen(m_Sock,5);
    //启动线程
    AfxBeginThread(&thread,0);
}======================================================================
客户端连接：m_Cli.sin_addr.s_addr=inet_addr(m_strIP);  //m_strIP为服务端IP
m_Cli.sin_family=AF_INET;
m_Cli.sin_port=5000;m_Sock=socket(AF_INET,SOCK_STREAM,0);
m_ctlOutput.SetWindowText(_T("正在连接服务器"));if (connect(dlg->m_Sock,(sockaddr*)&(dlg->m_Cli),sizeof(dlg->m_Cli))==0)
{
    dlg->m_ctlOutput.SetWindowText(_T("连接成功"));
}
else
{
    dlg->m_ctlOutput.SetWindowText(_T("连接失败"));
    return 0;
}
AfxBeginThread(thread,0);