PPTP-VPN on Stock Kernel
Attention: What ever you do, you do it on your own risk
You have to have firmware 1.34 already installed and opened for telnet access. If not, you can find a guide here: Open Stock Firmware LS-XHL
You need to have the optware IPKG system installed on your device. If not, you can find a guide here: Ipkg_on_the_Linkstation_(for_end-users)
For enabling the Microsoft MPPE-Encryption we need a kernel-Module that can be loaded by the stock kernel. For this you need to download the following package:
For Firmwares before 1.34 this also may work, but it's unknown if the needed Kernel-Modules are also available.
What's the aim
The aim is to realize a PPTP VPN-Server, that allows users to dial in, establish a PPTP-Tunnel, and work remotely on the LS (or your network).
What is needed
The good news are: if you have downloaded the package above, and if you are running Firmware 1.34 with the optware IPKG Feed, the basics are there.
The bad news: we need to add a kernel-module, the PPTP-Server (POPTOP) and need to configure the things.
How to install the MPPE Kernel Module
Untar the package "nobody.tgz". You will find a new kernel-file and a module-archive "modules.tar". Forget the kernel-file, as we don't need that. Untar the module-archive "modules.tar".
In there you will find the following path: /drivers/net/ In this path you will find the file: ppp_mppe.ko
You need to copy this file to the modules directory of your Linkstation /lib/modules/%kernel-version%/kernel/drivers/net
Now you need to edit the file /etc/modules.conf and ADD the following:
alias tty-ldisc-3 ppp_async alias tty-ldisc-14 ppp_synctty alias ppp-compress-18 ppp_mppe alias ppp-compress-21 bsd_comp alias ppp-compress-24 ppp_deflate alias ppp-compress-26 ppp_deflate alias net-pf-47 ip_gre
Now we need to update the module-library. Just execute the following command:
OK, now the kernel-module is installed, and MPPE Encryption is available.
How to install the PPTP-Server
We are using the OpenSource project POPTOP as PPTP-Server. This is available in the optware feed, therefore install it with the following command:
ipkg install POPTOP
We need to note, that POPTOP is now installed with the base-dir of /opt (like all the optware-packages)
Now we need to modify the start-script of POPTOP, as there is an issue with calling the daemon. So we need to edit the file: /opt/etc/init.d/S20poptop
Line 11 in the script (starting the daemon) should look like this: /opt/sbin/pptpd -c /opt/etc/pptpd.conf -o /etc/ppp/options.pptpd -p /var/run/pptpd.pid
The aim is, to avoid loading something from nvram (as stated originally there), because nothing can be read from nvram.