我在 Windows 7 上遇到了一个有趣的问题，几个客户的 OpenVPN 客户端不断连接和断开与我的 Ubuntu 10.04 LTS 服务器的连接。我能够使用 OSX、iPhone、iPad、Android 连接到同一台服务器，但出于某种原因，一些 Windows 7 客户端出现问题。
客户端版本为OpenVPN 2.1.3 i686-pc-mingw32 [SSL] [LZO2] [PKCS11]，构建于2010年8月20日
通过检查客户端的日志，以下行是可疑的：
Route addition via IPAPI succeeded [adaptive]
在服务器上，下面这一行同样可疑：
CTRL: Ignored a SET LINK INFO packet with real ACCMs!
我无法找到客户端仅在 Windows 7 中出现问题的任何原因，并且我不确定为什么服务器会忽略其设置的链接信息包。
Windows 7 中的 OpenVPN 客户端具有以下内容：
Sun Aug 14 23:39:04 2011 TEST ROUTES: 1/1 succeeded len=0 ret=1 a=0 u/d=up
Sun Aug 14 23:39:04 2011 C:\WINDOWS\system32\route.exe ADD 212.117.170.76 MASK 255.255.255.255 192.168.2.1
Sun Aug 14 23:39:04 2011 ROUTE: CreateIpForwardEntry succeeded with dwForwardMetric1=100 and dwForwardType=4
Sun Aug 14 23:39:04 2011 Route addition via IPAPI succeeded [adaptive]
Sun Aug 14 23:39:04 2011 C:\WINDOWS\system32\route.exe ADD 0.0.0.0 MASK 128.0.0.0 10.24.125.1
Sun Aug 14 23:39:04 2011 ROUTE: CreateIpForwardEntry succeeded with dwForwardMetric1=30 and dwForwardType=4
Sun Aug 14 23:39:04 2011 Route addition via IPAPI succeeded [adaptive]
Sun Aug 14 23:39:04 2011 C:\WINDOWS\system32\route.exe ADD 128.0.0.0 MASK 128.0.0.0 10.24.125.1
Sun Aug 14 23:39:04 2011 ROUTE: CreateIpForwardEntry succeeded with dwForwardMetric1=30 and dwForwardType=4
Sun Aug 14 23:39:04 2011 Route addition via IPAPI succeeded [adaptive]
Sun Aug 14 23:39:04 2011 Initialization Sequence Completed
Sun Aug 14 23:39:05 2011 Connection reset, restarting [-1]
Sun Aug 14 23:39:05 2011 TCP/UDP: Closing socket
Sun Aug 14 23:39:05 2011 C:\WINDOWS\system32\route.exe DELETE 212.117.170.76 MASK 255.255.255.255 192.168.2.1
Sun Aug 14 23:39:05 2011 Route deletion via IPAPI succeeded [adaptive]
服务器上的日志显示如下：
Aug 16 06:52:51 pppd[27924]: Connect: ppp27 <--> /dev/pts/28
Aug 16 06:52:57 pppd[27924]: Unsupported protocol 'IPv6 Control Protocol' (0x8057) received
Aug 16 06:52:58 pptpd[27923]: CTRL: Ignored a SET LINK INFO packet with real ACCMs!
Aug 16 06:53:00 pppd[27924]: local IP address 10.42.124.1
Aug 16 06:53:00 pppd[27924]: remote IP address 10.42.124.34
Aug 16 06:53:01 pppd[27924]: MPPE 128-bit stateless compression enabled
Aug 16 06:53:03 pppd[27924]: MPPE disabled
Aug 16 06:53:03 pppd[27924]: Connect time 0.1 minutes.
Aug 16 06:53:03 pppd[27924]: Sent 390 bytes, received 540 bytes.
Aug 16 06:53:09 pppd[27924]: Connection terminated.
Aug 16 06:53:09 pppd[27924]: write: Bad file descriptor (9)
Aug 16 06:53:09 pppd[27924]: Modem hangup
Aug 16 06:53:09 pppd[27924]: Exit.