Connecting to a PPTP VPN from an OpenVZ CentOS VPS

When setting up the PPTP and PPP packages on an OpenVZ VPS in order to connect to a VPN, there are a few extra steps you need to take that you don’t have to do with a non-virtualized box.

First, you have to load the following kernel modules on the hardware node and/or set them to automatically start during the boot up process:

modprobe ppp_mppe
modprobe ppp_deflate
modprobe zlib_deflate
modprobe ppp_async
modprobe ppp_generic
modprobe slhc
modprobe crc_ccitt

After doing that you should see something similiar to this when running lsmod

[root@me ~]# lsmod | grep ppp
ppp_mppe 39816 0
ppp_deflate 39168 0
zlib_deflate 52760 1 ppp_deflate
ppp_async 45056 0
ppp_generic 63632 4 ppp_mppe,ppp_deflate,ppp_async
slhc 39680 1 ppp_generic
crc_ccitt 35200 1 ppp_async

Second, you have to tweak the VPS’s conf file:

vzctl stop [VEnumber]
vzctl set [VEnumber] --features ppp:on --save
vzctl start [VEnumber]
vzctl set [VEnumber] --devices c:108:0:rw --save
vzctl exec [VEnumber] mknod /dev/ppp c 108 0
vzctl exec [VEnumber] chmod 600 /dev/ppp

Once that’s done, you canĀ follow theĀ normal instructions.

After that, you might need to uncomment the require-mppe-128 or mppe required,stateless line in /etc/ppp/options.pptp (depending on the VPN server). You may also need to manually create a static route to the network, with route add -net netmask ppp0.

You can check /var/log/messages for details about negotiation errors.

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