我有一个 PPTP 服务器正在运行，我可以从 linux 连接到它。当我从 Windows 7（测试 2 个实例）尝试时，它失败了。这是这样一个 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
我用mtu玩过，从900到1500都没有成功。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 我
在哪里109.xxx.158.201，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，我无法从那个 tcpdump 中理解 jack。暂停:)