VPN PPTP connection problem

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VPN PPTP connection problem

Hy @ all!

I asked google, and searched the discussion forum for a solution, but without success.
Thats my problem:

I'm trying to connect my university-network via VPN PPTP .
With a PC XP-Home plattform it works without problems.

When i'm trying to connect the VPN with OS X 10.5.3 the OS says, that the connection can't be established.
In the system-log i can find following entries:

+14.06.08 14.06.08 23:22:14 pppd[576] pppd 2.4.2 (Apple version 314) started by root, uid 501+
+14.06.08 14.06.08 23:22:24 pppd[576] PPTP connecting to server 'URL' (IPADRESS)...+
+14.06.08 14.06.08 23:22:24 pppd[576] PPTP connection established.+
+14.06.08 14.06.08 23:22:24 pppd[576] Connect: ppp0 <--> socket[34:17]+
+14.06.08 14.06.08 23:22:27 pppd[576] Refusing MPPE stateful mode offered by peer+
+14.06.08 14.06.08 23:22:27 pppd[576] MPPE required but peer negotiation failed+
+14.06.08 14.06.08 23:22:27 pppd[576] Connection terminated.+
+14.06.08 14.06.08 23:22:27 pppd[576] PPTP disconnecting...+
+14.06.08 14.06.08 23:22:27 pppd[576] PPTP disconnected+

I'm connected to the internet with a Netgear DG834GB router.

I hope you can help me.

MacBook Pro 15", Mac OS X (10.5.3)

Posted on Jun 14, 2008 2:56 PM

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Answer 1

RodneyW

Level 4

3,041 points

Jun 15, 2008 6:20 PM in response to JuNkY84

From what I have read, this relates to a problem with either the VPN server of the network you are connecting to (using 40 bit encryption rather than 128 bit), or with your ISP:

Try this old apple support note:

http://docs.info.apple.com/article.html?artnum=107706

Note that turning encryption OFF means that your network is now just a tunnel, rather than an encrypted tunnel.

Cheers,

Rodney

For your reference: There is an article on the same issue (for linux clients) that refers to the encryption level problem:
http://pptpclient.sourceforge.net/howto-diagnosis-2003-08-12.phtml

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Answer 2

RodneyW

Level 4

3,041 points

Jun 15, 2008 6:34 PM in response to RodneyW

One more article (I kept going through Google.. interesting issue).

http://office20.blogspot.com/2006/06/vpn-howto-linksys-dd-wrt-pptp-mac-os-x.html

This one (from Tiger days) suggests that the OS X VPN client requires that the router force encryption. If the router doesn't do this, then you get the problem.

Also, I just noticed that the Leopard VPN client does give you the option to use 40 bit encryption, or forcing 128 bit. Try using the "other" of those settings before you try "None".

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Answer 3

Jun 15, 2008 6:59 PM in response to RodneyW

Yeah, I had this problem when I was setting up my Leopard server. The LDAP directory was not properly authenticating the VPN service, and this error was appearing in the logs. While I could have delved deep into the problem, it was a fresh install so I reinstalled the OS and started services in the proper order. Now that the server is properly configured the VPN connections work fine.

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Answer 4

JuNkY84 Author

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Jun 16, 2008 10:57 AM in response to JuNkY84

Hy!
Thank you for replying my post 😉

I also disabled the encryption of the PPTP connection like it's written in the apple article but it didn't fix the problem. Even my windows pc connects to the server with a 128bit encryption. So in my opinion the ISP , the server and/or the router shouldn't be the problem.
I think the encryption of 40 oder 128 Bit is required by the server and i don't have the possibility to change that or am I wrong? My VPN skills are not the best.

I'll give you the logs for every encryption version (the 128 or 40 bit version is at the top of my article):
- Encryption: maximum (only 128Bit):

16.06.08 16.06.08 19:50:17 pppd[525] pppd 2.4.2 (Apple version 314) started by root, uid 501
16.06.08 16.06.08 19:50:17 pppd[525] PPTP connecting to server 'URL' (IPADRESS)...
16.06.08 16.06.08 19:50:17 pppd[525] PPTP connection established.
16.06.08 16.06.08 19:50:17 pppd[525] Connect: ppp0 <--> socket[34:17]
16.06.08 16.06.08 19:50:20 pppd[525] Refusing MPPE stateful mode offered by peer
16.06.08 16.06.08 19:50:20 pppd[525] MPPE required but peer negotiation failed
16.06.08 16.06.08 19:50:20 pppd[525] Connection terminated.
16.06.08 16.06.08 19:50:20 pppd[525] PPTP disconnecting...
16.06.08 16.06.08 19:50:20 pppd[525] PPTP disconnected
____________________________________________________________________
- Encryption: none:

16.06.08 16.06.08 19:53:00 pppd[536] pppd 2.4.2 (Apple version 314) started by root, uid 501
16.06.08 16.06.08 19:53:00 pppd[536] PPTP connecting to server'URL' (IPADRESS)...
16.06.08 16.06.08 19:53:00 pppd[536] PPTP connection established.
16.06.08 16.06.08 19:53:00 kernel pptp_input unexpected, so = 0x5470000, len = 13
16.06.08 16.06.08 19:53:00 pppd[536] Connect: ppp0 <--> socket[34:17]
16.06.08 16.06.08 19:53:03 pppd[536] Unsupported protocol 'Compression Control Protocol' (0x80fd) received
16.06.08 16.06.08 19:53:03 pppd[536] Connection terminated.
16.06.08 16.06.08 19:53:03 pppd[536] PPTP disconnecting...
16.06.08 16.06.08 19:53:03 pppd[536] PPTP disconnected
____________________________________________________________________

And maybe I described it a little bit wrong, but the server i'm connecting to is not "my" server, it's the server of the university i'm studying.

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Answer 5

RodneyW

Level 4

3,041 points

Jun 16, 2008 8:36 PM in response to JuNkY84

No worries. I undertand that it isn't your server... which definitely puts the onus on us to work something out!

Further digging suggests that this could be a bug in pppd (point to point protocal daemon), or possibly a mis-configuration of the pppd on your Mac.

pppd is the process that controls the VPN sign-up. The default mode of pppd is to [refuse mppe-stateful connections unless otherwise specified|http://ppp.samba.org/ppp/pppd.html] (find mppe-stateful on that page).

According to the specs, the settings are specified in /etc/ppp/options.pptp. However there are [fairly recent reports from Linux users that pppd is ignoring the settings anyway|https://bugs.launchpad.net/ubuntu/ source/network-manager-pptp/bug/125522].

I have inspected my own /etc/ppp directory and found nothing there. If you are feeling adventurous, you can create your own options.pptp and see if it works!

p.s. i am fairly sure that Apple uses the samba based version of pppd, I just don't know WHICH version number yet!

Message was edited by: RodneyW

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Answer 6

JuNkY84 Author

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Jun 17, 2008 1:56 AM in response to RodneyW

holy cow ... I just did it 😀 😀 😀
This might be a bug of OSX.
Here my description:

After Rodney told me to look for the options.pptp file in my sys I checked that aaaaand ... found nothing. Then I asked google again for this issue but with the options.pptp as additional keyword. I found an article somebody described a similar problem, and he gave the advice to create a new location profile in the system preferences > network. I was sure that this won't help .... BUT IT DID! Somewhere deeeeeeeep in Leopard there must be a file with this profiles which you can't edit the normal way with the systemprefs. You only have to create a new location (you can copy the old one too) and create the VPN connection, and hey ... it works 😉

So thanks a lot, and I hope if somebody has the same problem he'll find this thread and fix it 😉

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Answer 7

RodneyW

Level 4

3,041 points

Jun 17, 2008 2:16 AM in response to JuNkY84

Wunderbar!!

Out of interest, were you using the built in "Automatic" location previously? Or one that had been previously migrated from Tiger?

Tchuss!

Rodney

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Answer 8

JuNkY84 Author

Level 1

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Jun 17, 2008 2:45 AM in response to RodneyW

Yes we used the built in "Automatic" location.

Tschüss! 😉

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Answer 9

Jun 27, 2008 11:35 PM in response to JuNkY84

Thanks! I had the exact same VPN problem. I created a new network location, and it's fixed!!! I can't tell you how frustrated I've been trying to figure this out! THANK YOU!

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Answer 10

Sep 22, 2008 9:57 PM in response to moodyglasgow

I just wanted to say I've struggled with this for WEEKS. I can't believe making a new location fixed it, but it did for me as well. The funny thing is that I did it by accident, then found this page after the fact.

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Answer 11

Nov 25, 2008 5:50 PM in response to haydentech

Man I thought FOR SURE this was going to be the post that resolved my leopard pptp problems but it didn't work 😟 . If anyone can help me out with similar issues/problems my post in entirety is here http://discussions.apple.com/message.jspa?messageID=8256494#8256494 . Thank you!

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