Can not establish internet connection

[mintIng]

Hello OpenVPN Community,

I can not extablish the internet connection after activating the vpn-connection to the server of my university. The vpn client can establish connection to the vpn server.
I have already spent a lot of time trying to solve this problem. Without success. Can anybody help me?
I'm using Ubuntu 12.04.
Here is my log output:
Aug 12 14:13:08 USER NetworkManager[740]: <info> Starting VPN service 'openvpn'...
Aug 12 14:13:08 USER NetworkManager[740]: <info> VPN service 'openvpn' started (org.freedesktop.NetworkManager.openvpn), PID 2357
Aug 12 14:13:08 USER NetworkManager[740]: <info> VPN service 'openvpn' appeared; activating connections
Aug 12 14:13:08 USER NetworkManager[740]: <info> VPN plugin state changed: starting (3)
Aug 12 14:13:08 USER NetworkManager[740]: <info> VPN connection 'dhbw-client2' (Connect) reply received.
Aug 12 14:13:08 USER nm-openvpn[2361]: OpenVPN 2.2.1 x86_64-linux-gnu [SSL] [LZO2] [EPOLL] [PKCS11] [eurephia] [MH] [PF_INET6] [IPv6 payload 20110424-2 (2.2RC2)] built on Mar 30 2012
Aug 12 14:13:09 USER nm-openvpn[2361]: WARNING: No server certificate verification method has been enabled. See http://openvpn.net/howto.html#mitm for more info.
Aug 12 14:13:09 USER nm-openvpn[2361]: NOTE: the current --script-security setting may allow this configuration to call user-defined scripts
Aug 12 14:13:09 USER nm-openvpn[2361]: LZO compression initialized
Aug 12 14:13:09 USER nm-openvpn[2361]: UDPv4 link local: [undef]
Aug 12 14:13:09 USER nm-openvpn[2361]: UDPv4 link remote: [AF_INET]193.197.62.35:1198
Aug 12 14:13:10 USER nm-openvpn[2361]: [nacs.ba-stuttgart.de] Peer Connection Initiated with [AF_INET]193.197.62.35:1198
Aug 12 14:13:12 USER nm-openvpn[2361]: TUN/TAP device tun0 opened
Aug 12 14:13:12 USER nm-openvpn[2361]: /usr/lib/NetworkManager/nm-openvpn-service-openvpn-helper tun0 1500 1542 10.14.40.226 10.14.40.225 init
Aug 12 14:13:12 USER NetworkManager[740]: SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/tun0, iface: tun0)
Aug 12 14:13:12 USER NetworkManager[740]: SCPlugin-Ifupdown: device added (path: /sys/devices/virtual/net/tun0, iface: tun0): no ifupdown configuration found.
Aug 12 14:13:12 USER NetworkManager[740]: <info> VPN connection 'dhbw-client2' (IP Config Get) reply received.
Aug 12 14:13:12 USER NetworkManager[740]: <info> VPN Gateway: 193.197.62.35
Aug 12 14:13:12 USER NetworkManager[740]: <info> Internal Gateway: 10.14.40.225
Aug 12 14:13:12 USER NetworkManager[740]: <info> Tunnel Device: tun0
Aug 12 14:13:12 USER NetworkManager[740]: <info> Internal IP4 Address: 10.14.40.226
Aug 12 14:13:12 USER NetworkManager[740]: <info> Internal IP4 Prefix: 32
Aug 12 14:13:12 USER NetworkManager[740]: <info> Internal IP4 Point-to-Point Address: 10.14.40.225
Aug 12 14:13:12 USER NetworkManager[740]: <info> Maximum Segment Size (MSS): 0
Aug 12 14:13:12 USER nm-openvpn[2361]: Initialization Sequence Completed
Aug 12 14:13:12 USER NetworkManager[740]: <info> Static Route: 10.200.0.0/16 Next Hop: 10.200.0.0
Aug 12 14:13:12 USER NetworkManager[740]: <info> Static Route: 10.14.0.1/32 Next Hop: 10.14.0.1
Aug 12 14:13:12 USER NetworkManager[740]: <info> Forbid Default Route: no
Aug 12 14:13:12 USER NetworkManager[740]: <info> DNS Domain: '(none)'
Aug 12 14:13:13 USER dnsmasq[2339]: exiting on receipt of SIGTERM
Aug 12 14:13:13 USER NetworkManager[740]: <info> DNS: starting dnsmasq...
Aug 12 14:13:13 USER NetworkManager[740]: <info> (tun0): writing resolv.conf to /sbin/resolvconf
Aug 12 14:13:13 USER dnsmasq[2367]: started, version 2.59 cache disabled
Aug 12 14:13:13 USER dnsmasq[2367]: compile time options: IPv6 GNU-getopt DBus i18n DHCP TFTP conntrack IDN
Aug 12 14:13:13 USER dnsmasq[2367]: warning: no upstream servers configured
Aug 12 14:13:13 USER NetworkManager[740]: <info> VPN connection 'dhbw-client2' (IP Config Get) complete.
Aug 12 14:13:13 USER NetworkManager[740]: <info> Policy set 'dhbw-client2' (tun0) as default for IPv4 routing and DNS.
Aug 12 14:13:13 USER dbus[553]: [system] Activating service name='org.freedesktop.nm_dispatcher' (using servicehelper)
Aug 12 14:13:13 USER NetworkManager[740]: <info> VPN plugin state changed: started (4)
Aug 12 14:13:13 USER dbus[553]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Aug 12 14:13:13 USER ntpdate[2389]: Can't find host ntp.ubuntu.com: Name or service not known (-2)
Aug 12 14:13:13 USER ntpdate[2389]: no servers can be used, exiting