[PROBLEM] Trouble with PPTP or L2TP VPN connection

[kraleksandr]

When I trying to set up pptp-VPN (pptp-linux) or l2tp-VPN (xl2tpd), my wireless network (usb-wifi) becomes offline. Is there any reason for that?
If I use wired connection, l2tp connects successfully and network works.

Code:

xbian@xbian ~ $ sudo ifconfig
eth0      Link encap:Ethernet  HWaddr b8:27:eb:17:b2:8b  
          inet addr:192.168.1.108  Bcast:192.168.1.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:180227 errors:0 dropped:0 overruns:0 frame:0
          TX packets:179018 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:71903417 (68.5 MiB)  TX bytes:49917956 (47.6 MiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:14 errors:0 dropped:0 overruns:0 frame:0
          TX packets:14 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:1404 (1.3 KiB)  TX bytes:1404 (1.3 KiB)

ppp0      Link encap:Point-to-Point Protocol  
          inet addr:172.22.24.9  P-t-P:172.22.24.1  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1500  Metric:1
          RX packets:14 errors:0 dropped:0 overruns:0 frame:0
          TX packets:7 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:3
          RX bytes:670 (670.0 B)  TX bytes:70 (70.0 B)

wlan0     Link encap:Ethernet  HWaddr 6c:fd:b9:60:60:b4  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:611 errors:0 dropped:1 overruns:0 frame:0
          TX packets:22 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:75676 (73.9 KiB)  TX bytes:6454 (6.3 KiB)

Code:

xbian@xbian ~ $ sudo cat /etc/network/interfaces
auto lo

iface lo inet loopback
iface eth0 inet dhcp

allow-hotplug wlan0
iface wlan0 inet manual

wpa-roam /etc/wpa_supplicant/wpa-roam.conf

iface default inet dhcp
xbian@xbian ~ $ sudo cat /etc/wpa_supplicant/wpa-roam.conf
update_config=1

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev

network={
        ssid="wifi"
        psk="pass"
        id_str="home"
}

xl2tpd config

Code:

[global]
access control = yes

[lac sevstar]
lns = vpn.com
autodial = yes
redial = yes
redial timeout = 3
require authentication = no
ppp debug = no
pppoptfile = /etc/ppp/options.xl2tpd

/etc/ppp/options.xl2tpd

Code:

xbian@xbian ~ $ sudo cat /etc/ppp/options.xl2tpd
lock
noauth

nobsdcomp
nodeflate
noaccomp

refuse-eap
refuse-pap
refuse-chap
nomppe

mru 1500
mtu 1500

nopersist
maxfail 0
defaultroute

name login
password pass