Bug 917967

Summary: Unable to connect to VPN using PPTP
Product: [openSUSE] openSUSE Distribution Reporter: Graham Freeman <graham>
Component: NetworkAssignee: E-mail List <gnome-bugs>
Status: RESOLVED DUPLICATE QA Contact: E-mail List <qa-bugs>
Severity: Normal    
Priority: P5 - None CC: bwiedemann, chcao, max, novell.admin
Version: 13.2   
Target Milestone: ---   
Hardware: x86-64   
OS: openSUSE 13.2   
Whiteboard:
Found By: --- Services Priority:
Business Priority: Blocker: ---
Marketing QA Status: --- IT Deployment: ---
Attachments: Tail of journalctl immediately after attempting VPN connection with OpenSUSE
Tail of journalctl from Fedora when the VPN connection has been made successfully

Description Graham Freeman 2015-02-15 00:22:57 UTC
Created attachment 623312 [details]
Tail of journalctl immediately after attempting VPN connection with OpenSUSE

I have recently installed OpenSUSE on a Toshiba laptop. I have been unable to connect using VPN to an external server machine that uses MS and PPTP for communication. I am able to connect to the same server using my old laptop running Fedora 18, so I am looking for advice on what I need to do differently under OpenSUSE.

One problem I encountered on Fedora was the need to set MTU=1200 in the /etc/sysconfig/network-scripts ifcfg-... file I was using. I have tried settkng MTU in the equivalent file in OpenSUSE, but it has not helped. I am able to get the logs from the two machines and the problem seems to be that in OpenSUSE I get the message "The synchronous pptp option is NOT activated" which is absent under Fedora.

The settings that I am using on both machines are:
PPTP connection type
NT Domain: AD
PPTP options: Use Point-to-Point encryption (MPPE), MSCHAP and MSCHAP2

I have installed NetworkManager-pptp, NetworkManager-pptp-gnome, NetworkManager-pptp-lang, plasma-nm-pptp, plasma-nm-pptp, pptp, pptpd.
Comment 1 Graham Freeman 2015-02-15 00:26:35 UTC
Created attachment 623313 [details]
Tail of journalctl from Fedora when the VPN connection has been made successfully
Comment 2 Graham Freeman 2015-02-16 00:58:46 UTC
I am sorry for posting this to the Bugzilla site. I had intended sending it to the forum (which I have since done so). It is good to have a common login for bugzilla and the forum, but it caught me out this time. I have no evidence that this is a bug yet.
Comment 3 Bernhard Wiedemann 2015-02-21 15:36:03 UTC
note: pptp's security is known to be broken
and thus the general advice is to not use it anymore
Comment 4 Graham Freeman 2015-02-22 06:18:03 UTC
The problem I face is that I do contract work for my old employer who have a MS Windows server. The only instructions they have given me to connect to their site is via their VPN using PPTP. Although I would prefer a secure connection to their server, at present the only connection available to me from my Linux box is using NetworkManager. I am still able to use a five-year-old computer with an old version of Fedora, but I am concerned at the machine's reliability. Is PPTP no longer supported with NetworkManager? I will ask my old employer's technical staff if they have an alternative to PPTP, but as I am now an outsider I do not have much influence anymore.
Comment 5 Chenzi Cao 2015-03-02 07:54:12 UTC
Hi Reinhard, would you please kindly help to have a look at here? I'm not quite sure whether it is right to assign it to you, please feel free to reassign whenever necessary, thank you!
Comment 6 Reinhard Max 2015-03-02 14:36:45 UTC
Looks to me like a problem in the settings that NetworkManager passes to pptp.
Comment 7 Zsolt Sági 2015-05-14 10:36:36 UTC
The problem is that there is a bug in SuSEfirewall2 and if the firewall is activated, it somehow DROPS incoming GRE packages in spite the fact that we are the connection initiating client - not the server. It might be some conntrack / state issue. Adding a line to the INPUT chain seems to help:

iptables -I INPUT -p gre -j ACCEPT

Disabling the firewall entirely also solves the problem. However, I think the firewall should be fixed in order to allow outgoing GRE communication.
Comment 8 Zsolt Sági 2015-05-14 10:41:30 UTC
https://bugzilla.opensuse.org/show_bug.cgi?id=917967#c7

*** This bug has been marked as a duplicate of bug 930896 ***