Ubuntu 12.04 why is my pptp server failing when encryption is turned on?

[heavylifting]

Ok so I have setup a PPTPD server and configured it appropriately.

Here is my pptpd-options:

name pptpd
require-mschap-v2
require-mppe-128
ms-dns 8.8.8.8
ms-dns 8.8.4.4
proxyarp
nodefaultroute
debug
lock
nobsdcomp

Here is my pptpd.conf:

option /etc/ppp/pptpd-options
debug
logwtmp
localip 192.168.1.241
remoteip 192.168.1.234-238,192.168.1.245

Here is my chap-secrets:

username pptpd password  *

My problem is that when I turn on require-mschap-v2 and\or require-mppe-128 that the connection fails and produces the following error.

Dec 27 16:18:51 mmweb1 pppd[3252]: Plugin /usr/lib/pptpd/pptpd-logwtmp.so loaded.
Dec 27 16:18:51 mmweb1 pppd[3252]: pptpd-logwtmp: $Version$
Dec 27 16:18:51 mmweb1 pptpd[3251]: 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
Dec 27 16:18:51 mmweb1 pptpd[3251]: CTRL: PTY read or GRE write failed (pty,gre)=(6,7)
Dec 27 16:18:51 mmweb1 pptpd[3251]: CTRL: Reaping child PPP[3252]
Dec 27 16:18:51 mmweb1 pptpd[3251]: CTRL: Client 192.168.1.240 control connection 
finished
Dec 27 16:18:51 mmweb1 pptpd[3251]: CTRL: Exiting now
Dec 27 16:18:51 mmweb1 pptpd[3075]: MGR: Reaped child 3251

If I turn off require-mschap-v2 and require-mppe-128 I produce the following results and the connection succeeds and starts accepting packets.

Dec 27 16:30:18 mmweb1 pppd[3314]: Plugin /usr/lib/pptpd/pptpd-logwtmp.so loaded.
Dec 27 16:30:18 mmweb1 pppd[3314]: pptpd-logwtmp: $Version$
Dec 27 16:30:18 mmweb1 pptpd[3313]: GRE: Bad checksum from pppd.
Dec 27 16:30:18 mmweb1 pptpd[3313]: CTRL: Received PPTP Control Message (type: 15)
Dec 27 16:30:18 mmweb1 pptpd[3313]: CTRL: Got a SET LINK INFO packet with standard ACCMs

What I notice is that it always says that GRE: Bad checksum from pppd. It makes me wonder what exactly is messed up with GRE on the server. Please note that I am able to connection with encryption turned off so I don't think that it is my router or isp or anything else like that. Any help is greatly appreciated thanks!

I have also posted this question on www.superuser.com if anyone wants to receive reputation points there.

http://superuser.com/questions/52498...erver-properly

[sensibleusername]

Just running into this issue myself.

[heavylifting]

I still haven't found a solution to this problem and I actually started exploring OpenVPN. I got OpenVPN setup, Windows and Android can connect if I leave it as a TUN adapter.

However, if you need to use the TAP method so that your clients get a local LAN IP Android doesn't support it. Only Windows so far. IOS doesn't support OpenVPN at all right now.

This of course makes me want to circle back around to PPTP since its supported on all devices.

[heavylifting]

So I have found my problem. I was including special characters into my password that was causing the authentication to fail. Basically it wasn't recognizing my pass. Not sure if there are escape characters you could use to bypass that but that was my issue. Let me know what your problems are maybe I can help.