为什么当我告诉网口2194时，连接被拒绝了？

Question

我正在设置一个OpenVPN访问服务器，并且我不断地在我的客户端(S)上得到错误的“拒绝连接”。因此，我决定从一开始就开始调试(服务器)，并尝试了telnet 127.0.0.1 2194。结果：

openvpn_as_test_1:~$ telnet 127.0.0.1 2194
Trying 127.0.0.1...
telnet: Unable to connect to remote host: Connection refused

因此，这意味着问题在服务器上，所以我检查了端口是否在ufw中用sudo ufw status打开，并注意到防火墙不允许端口。在使用ufw allow 2194/udp (和ufw allow 2194/tcp，甚至在需要时)添加端口之后。在再次检查ufw status之后，结果如下：

Status: active

To                         Action      From
--                         ------      ----
2194/udp                   ALLOW       Anywhere
2194/tcp                   ALLOW       Anywhere
22                         ALLOW       Anywhere
2194/udp (v6)              ALLOW       Anywhere (v6)
2194/tcp (v6)              ALLOW       Anywhere (v6)
22 (v6)                    ALLOW       Anywhere (v6)

内部防火墙允许端口，所以我再次尝试了telnet 127.0.0.1 2194，猜猜看，仍然是connection refused：

openvpn_as_test_1:~$ telnet 127.0.0.1 2194
Trying 127.0.0.1...
telnet: Unable to connect to remote host: Connection refused

好吧，还有什么问题吗？也许telnet不能正常工作，所以我尝试了telnet 127.0.0.1 22：

openvpn_as_test_1:~$ telnet 127.0.0.1 22
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
SSH-2.0-OpenSSH_7.6p1 Ubuntu-4ubuntu0.3

太好了，telnet运行得很好。让我们检查netstat，看看我们是否监听端口2194：

openvpn_as_test_1:~$ netstat -al | grep "LISTEN"
tcp        0      0 0.0.0.0:943             0.0.0.0:*               LISTEN
tcp        0      0 localhost:domain        0.0.0.0:*               LISTEN
tcp        0      0 0.0.0.0:ssh             0.0.0.0:*               LISTEN
tcp        0      0 0.0.0.0:https           0.0.0.0:*               LISTEN
tcp        0      0 localhost:904           0.0.0.0:*               LISTEN
tcp        0      0 localhost:905           0.0.0.0:*               LISTEN
tcp        0      0 localhost:906           0.0.0.0:*               LISTEN
tcp        0      0 localhost:907           0.0.0.0:*               LISTEN
tcp        0      0 localhost:908           0.0.0.0:*               LISTEN
tcp        0      0 localhost:909           0.0.0.0:*               LISTEN
tcp6       0      0 [::]:ssh                [::]:*                  LISTEN
unix  2      [ ACC ]     SEQPACKET  LISTENING     13660    /run/udev/control
unix  2      [ ACC ]     STREAM     LISTENING     22260    /run/user/1000/systemd/private
unix  2      [ ACC ]     STREAM     LISTENING     22264    /run/user/1000/gnupg/S.gpg-agent.ssh
unix  2      [ ACC ]     STREAM     LISTENING     22265    /run/user/1000/snapd-session-agent.socket
unix  2      [ ACC ]     STREAM     LISTENING     22266    /run/user/1000/gnupg/S.dirmngr
unix  2      [ ACC ]     STREAM     LISTENING     22267    /run/user/1000/gnupg/S.gpg-agent.extra
unix  2      [ ACC ]     STREAM     LISTENING     22268    /run/user/1000/gnupg/S.gpg-agent.browser
unix  2      [ ACC ]     STREAM     LISTENING     22269    /run/user/1000/gnupg/S.gpg-agent
unix  2      [ ACC ]     STREAM     LISTENING     13568    /run/systemd/private
unix  2      [ ACC ]     STREAM     LISTENING     13578    /run/systemd/journal/stdout
unix  2      [ ACC ]     STREAM     LISTENING     16810    /run/uuidd/request
unix  2      [ ACC ]     STREAM     LISTENING     16816    /var/run/dbus/system_bus_socket
unix  2      [ ACC ]     STREAM     LISTENING     16828    /run/acpid.socket
unix  2      [ ACC ]     STREAM     LISTENING     16830    /run/snapd.socket
unix  2      [ ACC ]     STREAM     LISTENING     16832    /run/snapd-snap.socket
unix  2      [ ACC ]     STREAM     LISTENING     13662    /run/lvm/lvmpolld.socket
unix  2      [ ACC ]     STREAM     LISTENING     13839    /run/lvm/lvmetad.socket
unix  2      [ ACC ]     STREAM     LISTENING     16861    /var/lib/lxd/unix.socket
unix  2      [ ACC ]     STREAM     LISTENING     20300    /usr/local/openvpn_as/etc/sock/sagent
unix  2      [ ACC ]     STREAM     LISTENING     20303    /usr/local/openvpn_as/etc/sock/sagent.localroot
unix  2      [ ACC ]     STREAM     LISTENING     20304    /usr/local/openvpn_as/etc/sock/sagent.api
unix  2      [ ACC ]     STREAM     LISTENING     16865    @ISCSIADM_ABSTRACT_NAMESPACE

这里没有列出2194港口。好吧，现在我不知道怎么继续下去了。我的问题在哪里？

Answer 1

我认为您在ufw上允许了错误的端口:您尝试将端口2194用于telnet，并且根据您发布的ufw show status的输出允许端口1194。