我有一个PPTP服务器正在运行，我可以从linux连接到它。当我尝试从Windows 7（测试2个实例）它失败。这是conn的系统日志：
pptpd[540]: CTRL: Client 109.xxx.158.201 control connection started
pptpd[540]: CTRL: Starting call (launching pppd, opening GRE)
pppd[541]: Plugin radius.so loaded.
pppd[541]: RADIUS plugin initialized.
pppd[541]: Plugin radattr.so loaded.
pppd[541]: RADATTR plugin initialized.
pppd[541]: pppd 2.4.5 started by root, uid 0
pppd[541]: Using interface ppp0
pppd[541]: Connect: ppp0 <--> /dev/pts/1
pptpd[540]: GRE: Bad checksum from pppd.
pppd[541]: LCP: timeout sending Config-Requests
pppd[541]: Connection terminated.
pppd[541]: Modem hangup
pppd[541]: Exit.
pptpd[540]: GRE: read(fd=6,buffer=6075a0,len=8196) from PTY failed: status = -1 error = Input/output error, usually caused by unexpected termination of pppd, check option syntax and pppd logs
pptpd[540]: CTRL: PTY read or GRE write failed (pty,gre)=(6,7)
pptpd[540]: CTRL: Reaping child PPP[541]
pptpd[540]: CTRL: Client 109.xxx.158.201 control connection finished
我玩过mtu，从900到1500不等，没有成功。 我的pptp选项：
name pptpd
refuse-pap
refuse-chap
refuse-mschap
require-mschap-v2
require-mppe-128
proxyarp
nodefaultroute
lock
nobsdcomp
ms-dns 10.10.0.1
noipx
mtu 1404
mru 1404
记住！ Linux客户端连接，因此应启用端口和协议。
tcpdump -i eth0 port 1723 or proto 47显示以下要点：
https://gist.github.com/ciokan/5595640
其中109.xxx.158.201是我，客户。
客户端没有防火墙。一切都被禁用了。我不是网络管理员，我无法理解来自该tcpdump的插孔。哈尔普：）