I have a PPTP server running and I can connect to it from linux. When I try from windows 7 (2 instances tested) it fails. Here's the syslog for such a conn:
pptpd: CTRL: Client 109.xxx.158.201 control connection started pptpd: CTRL: Starting call (launching pppd, opening GRE) pppd: Plugin radius.so loaded. pppd: RADIUS plugin initialized. pppd: Plugin radattr.so loaded. pppd: RADATTR plugin initialized. pppd: pppd 2.4.5 started by root, uid 0 pppd: Using interface ppp0 pppd: Connect: ppp0 <--> /dev/pts/1 pptpd: GRE: Bad checksum from pppd. pppd: LCP: timeout sending Config-Requests pppd: Connection terminated. pppd: Modem hangup pppd: Exit. pptpd: 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: CTRL: PTY read or GRE write failed (pty,gre)=(6,7) pptpd: CTRL: Reaping child PPP pptpd: CTRL: Client 109.xxx.158.201 control connection finished
I played with the mtu and ranged it from 900 to 1500 with no success. My pptp options:
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
Remember! Linux client connects so ports and protocols should be enabled.
tcpdump -i eth0 port 1723 or proto 47 shows the following gist:
109.xxx.158.201 is me, the client.
No firewalls on client. Everything disabled. Im not a network admin and I can't understand jack from that tcpdump. HALP :)