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Using bubba as pptp server

Posted: 03 Aug 2007, 16:06
by redferret
Hello all,
I'm trying to setup my bubba server as a pptp server, but I've run ito some problems.
I have followed the instructions in the debian pptp howto http://poptop.sourceforge.net/dox/debian-howto.phtml but get the following printout in /var/log/messages:

Code: Select all

Aug  3 21:36:52 frodo pppd[14155]: pppd options in effect:
Aug  3 21:36:52 frodo pppd[14155]: debug^I^I# (from /etc/ppp/pptpd-options)
Aug  3 21:36:52 frodo pppd[14155]: nologfd^I^I# (from /etc/ppp/pptpd-options)
Aug  3 21:36:52 frodo pppd[14155]: dump^I^I# (from /etc/ppp/pptpd-options)
Aug  3 21:36:52 frodo pppd[14155]: require-mschap-v2^I^I# (from /etc/ppp/pptpd-options)
Aug  3 21:36:52 frodo pppd[14155]: refuse-pap^I^I# (from /etc/ppp/pptpd-options)
Aug  3 21:36:52 frodo pppd[14155]: refuse-chap^I^I# (from /etc/ppp/pptpd-options)
Aug  3 21:36:52 frodo pppd[14155]: refuse-mschap^I^I# (from /etc/ppp/pptpd-options)
Aug  3 21:36:52 frodo pppd[14155]: name pptpd^I^I# (from /etc/ppp/pptpd-options)
Aug  3 21:36:52 frodo pppd[14155]: 115200^I^I# (from command line)
Aug  3 21:36:52 frodo pppd[14155]: lock^I^I# (from /etc/ppp/pptpd-options)
Aug  3 21:36:52 frodo pppd[14155]: local^I^I# (from command line)
Aug  3 21:36:52 frodo pppd[14155]: novj^I^I# (from /etc/ppp/pptpd-options)
Aug  3 21:36:52 frodo pppd[14155]: novjccomp^I^I# (from /etc/ppp/pptpd-options)
Aug  3 21:36:52 frodo pppd[14155]: ipparam 192.168.1.150^I^I# (from command line)
Aug  3 21:36:52 frodo pppd[14155]: ms-dns xyz # [don't know how to print value]^I^I# (from /etc/ppp/pptpd-options)
Aug  3 21:36:52 frodo pppd[14155]: ms-wins xyz # [don't know how to print value]^I^I# (from /etc/ppp/pptpd-options)
Aug  3 21:36:52 frodo pppd[14155]: proxyarp^I^I# (from /etc/ppp/pptpd-options)
Aug  3 21:36:52 frodo pppd[14155]: 192.168.1.60:192.168.1.61^I^I# (from command line)
Aug  3 21:36:52 frodo pppd[14155]: nobsdcomp^I^I# (from /etc/ppp/pptpd-options)
Aug  3 21:36:52 frodo pppd[14155]: require-mppe-128^I^I# (from /etc/ppp/pptpd-options)
Aug  3 21:36:52 frodo pppd[14155]: pppd 2.4.3 started by root, uid 0
Aug  3 21:36:52 frodo pppd[14155]: Using interface ppp0
Aug  3 21:36:52 frodo pppd[14155]: Connect: ppp0 <--> /dev/pts/1
Aug  3 21:37:22 frodo pppd[14155]: LCP: timeout sending Config-Requests
Aug  3 21:37:22 frodo pppd[14155]: Connection terminated.
Aug  3 21:37:22 frodo pppd[14155]: Using interface ppp0
Aug  3 21:37:22 frodo pppd[14155]: Connect: ppp0 <--> /dev/pts/1
Aug  3 21:37:22 frodo pppd[14155]: tcflush failed: Bad file descriptor
Aug  3 21:37:23 frodo pppd[14155]: Exit.
Aug  3 21:37:23 frodo ifplugd.hotplug[14181]: Stopping ifplugd for ppp0

Any ideas on the how to solve this?

Posted: 03 Aug 2007, 17:40
by bjorn
Hi,

As i remember PPTP uses GRE. Do you have GRE enabled in your kernel?
By the looks of it, my (default) kernel does not have GRE enabled. Excito crew should be able to confirm if it is or not...


Although your log doesn't mention it... It would be easier to troubleshoot if you explain a little what kind of issues you are experiencing.

/Björn

Posted: 03 Aug 2007, 17:58
by redferret
Hi again,

Thanks for the response and sorry for missing the error description. When trying to connect from a WinXP machine using the standard VPN connectivity, the setup fails when doing the username authentication. The dialoge box hangs for 30 secs, which corresponds well to the delay in conjunction with the LCP timeout seen in the log.
I have not checked the kernel for GRE, but I use the default kernel, so I guess I don't have GRE enabled either...

Posted: 03 Aug 2007, 18:31
by bjorn
Oh, i just remembered.

Excito has published some kernel modules, and GRE is one of them. Lucky you :P

http://excito.org/forum/viewtopic.php?t=452

Good luck!

Posted: 05 Aug 2007, 17:15
by redferret
Just tried inserting ip_gre module, but the same problem persists. Digging around some more, it looks like another module is needed, namely ppp_mppe (encryption for ppp). I will setup crosstool and see if I can compile the needed module.

Posted: 08 Aug 2007, 17:55
by redferret
I've installed crosstool and compiled the missing module (ppp_mppe). However, when I try to install the new module using modprobe, I get an error message that the following symbols are missing:

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ppp_mppe: Unknown symbol crypto_alloc_tfm
ppp_mppe: Unknown symbol crypto_free_tfm
ppp_mppe: Unknown symbol crypto_alg_available
After a little bit of digging, it seems as if these functions are defined in the crypto base (crypto/api.c), which I haven't found a way to build as a module. The thing I find strrange here is that the exito config file for building the kernel includes crypto support, shouldn't the base api be included then? (This seems to be the issue that is described in http://excito.org/forum/viewtopic.php?t=576 )

Is there something missing in the excito build configuration or am I misunderstanding something?

Posted: 16 Sep 2007, 14:15
by tester22
Did you manage to solve the problem with GRE?
I have the same problem and when I installed the extra kernel modules this messed up my boot sequence.

This is the log from my Bubba upon starting of a VPN session:
Sep 16 19:32:32 bubba pppd[15984]: pppd 2.4.3 started by root, uid 0
Sep 16 19:32:32 bubba pppd[15984]: Using interface ppp0
Sep 16 19:32:32 bubba pppd[15984]: Connect: ppp0 <--> /dev/pts/2
Sep 16 19:32:32 bubba pptpd[15983]: GRE: Bad checksum from pppd.
Sep 16 19:32:32 bubba pptpd[15983]: GRE: Discarding packet by header check
Sep 16 19:32:59 bubba last message repeated 19 times
Sep 16 19:33:02 bubba pppd[15984]: LCP: timeout sending Config-Requests
Sep 16 19:33:02 bubba pppd[15984]: Connection terminated.
Sep 16 19:33:02 bubba pptpd[15983]: CTRL: EOF or bad error reading ctrl packet length.
Sep 16 19:33:02 bubba pptpd[15983]: CTRL: couldn't read packet header (exit)
Sep 16 19:33:02 bubba pptpd[15983]: CTRL: CTRL read failed
Sep 16 19:33:02 bubba pptpd[15983]: CTRL: Reaping child PPP[15984]
Sep 16 19:33:02 bubba pppd[15984]: Failed to open /dev/pts/2: No such file or directory
Sep 16 19:33:02 bubba pppd[15984]: Modem hangup
Sep 16 19:33:02 bubba pppd[15984]: Exit.
Sep 16 19:33:02 bubba pptpd[15983]: CTRL: Client 80.251.192.5 control connection finished
Sep 16 19:33:03 bubba ifplugd.hotplug[16008]: Stopping ifplugd for ppp0
I am connecting from a Mac running Tiger and the VPN connection works then I connect to other servers.