我有一个正在运行的 PPTP 服务器，我可以从 Linux 连接到它。当我尝试从 Windows 7（测试了 2 个实例）连接时，它失败了。以下是此类连接的系统日志：
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
我玩了 mtu 并将其范围从 900 调到 1500，但没有成功。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 客户端连接时应启用端口和协议。
tcpdump -i eth0 port 1723 or proto 47显示以下要点：
https://gist.github.com/ciokan/5595640109.xxx.158.201我这个客户在 哪儿？
客户端上没有防火墙。一切都已禁用。我不是网络管理员，我无法理解 tcpdump 中的 jack。HALP :)