小编Chr*_*ian的帖子

I have a C-Media USB soundcard installed on my Raspberry Pi: Bus 001 Device 004: ID 0d8c:0008 C-Media Electronics, Inc.. It is a USB cable with an XLR end on the other side, to which I have an XLR Microphone (a Sennheiser MD 427 if anyone is interested) connected:

Connecting it to my Mac I can turn up the recording volume (it says "settings for selected device" and "input volume" in german) and I get a fairly ok recording …

我有多台机器打开到我的服务器的反向 ssh 连接。每台机器都使用不同的反向 ssh 端口，我用它来区分机器。我使用这些隧道从服务器登录机器（显然）：

me@server:~$ ssh -p 2219 root@localhost
Last login: Sun Jun  7 00:18:44 2015 from localhost
root@remote_machine:~#

远程机器使用完全不同的访问技术（DSL、VSAT、GPRS/EDGE/3G/4G），因此反向 ssh 连接的耐用性有所不同 - 这显然是问题所在。

这是nmap在较长空闲期后列出的内容（即，没有强制重启 ssh 隧道，见下文）：

me@server:~$ sudo nmap -sS -p 1000-3000 --open localhost

Starting Nmap 5.21 ( http://nmap.org ) at 2015-06-07 11:09 CEST
Nmap scan report for localhost (127.0.0.1)
Host is up (0.000014s latency).
Hostname localhost resolves to 2 IPs. Only scanned 127.0.0.1
Not shown: 1988 closed ports
PORT     STATE SERVICE
1133/tcp open  unknown
1270/tcp …