First of all, I've used this exact VPN client on 2 Windows machines and a Linux machine before, always working excellently. Now I'm unfortunately on a Windows machine, and I've installed Ubuntu in a VirtualBox VM in order to have a Linux environment to work in.
I'm using the Shrew Soft VPN client to connect to a Cisco Home Office VPN server.
The problem
As soon as I connect to the VPN using the client, DNS stops working. I can still ping IP addresses (e.g. 8.8.8.8) but packets still take the same route as without the VPN client running (checked using traceroute). All DNS lookups time out and fail. I am unable to ping any IP addresses in the network I'm connecting to.
My suspicion is that VirtualBox's "Guest Additions" are interfering with the VPN software in some way.
I've uninstalled VirtualBox Guest Additions and it made no difference :(
Any ideas?
Here is the ifconfig output before connecting:
enp0s3 Link encap:Ethernet HWaddr 08:00:27:c0:28:c3
inet addr:192.168.1.128 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::a00:27ff:fec0:28c3/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1887173 errors:0 dropped:1 overruns:0 frame:0
TX packets:810435 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1823228735 (1.8 GB) TX bytes:188693611 (188.6 MB)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:210862 errors:0 dropped:0 overruns:0 frame:0
TX packets:210862 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:19176186 (19.1 MB) TX bytes:19176186 (19.1 MB)And here it is after connecting:
enp0s3 Link encap:Ethernet HWaddr 08:00:27:c0:28:c3
inet addr:192.168.1.128 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::a00:27ff:fec0:28c3/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1906855 errors:0 dropped:2 overruns:0 frame:0
TX packets:817511 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1826304725 (1.8 GB) TX bytes:191434042 (191.4 MB)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:211373 errors:0 dropped:0 overruns:0 frame:0
TX packets:211373 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:19227460 (19.2 MB) TX bytes:19227460 (19.2 MB)
tap0 Link encap:Ethernet HWaddr 32:37:c2:69:d6:9d
inet addr:172.21.100.19 Bcast:172.21.100.255 Mask:255.255.255.0
inet6 addr: fe80::3037:c2ff:fe69:d69d/64 Scope:Link
UP BROADCAST RUNNING MTU:1380 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)These messages appear in the syslog when connecting:
Mar 23 21:35:39 beast-vm-ubuntu NetworkManager[842]: <info> (tap0): link connected
Mar 23 21:35:39 beast-vm-ubuntu systemd-udevd[13615]: Could not generate persistent MAC address for tap0: No such file or directory
Mar 23 21:35:39 beast-vm-ubuntu NetworkManager[842]: <info> (tap0): new Tun device (carrier: ON, driver: 'tun', ifindex: 9)
Mar 23 21:35:39 beast-vm-ubuntu NetworkManager[842]: <info> devices added (path: /sys/devices/virtual/net/tap0, iface: tap0)
Mar 23 21:35:39 beast-vm-ubuntu NetworkManager[842]: <info> device added (path: /sys/devices/virtual/net/tap0, iface: tap0): no ifupdown configuration found.
Mar 23 21:35:39 beast-vm-ubuntu NetworkManager[842]: <info> keyfile: add connection in-memory (ae12e1f9-cec0-4e2d-82cf-63736cc610db,"tap0")
Mar 23 21:35:39 beast-vm-ubuntu NetworkManager[842]: <info> (tap0): device state change: unmanaged -> unavailable (reason 'connection-assumed') [10 20 41]
Mar 23 21:35:39 beast-vm-ubuntu NetworkManager[842]: <info> (tap0): device state change: unavailable -> disconnected (reason 'connection-assumed') [20 30 41]
Mar 23 21:35:39 beast-vm-ubuntu NetworkManager[842]: <info> Device 'tap0' has no connection; scheduling activate_check in 0 seconds.
Mar 23 21:35:39 beast-vm-ubuntu NetworkManager[842]: <info> (tap0): Activation: starting connection 'tap0' (ae12e1f9-cec0-4e2d-82cf-63736cc610db)
Mar 23 21:35:39 beast-vm-ubuntu NetworkManager[842]: <info> (tap0): device state change: disconnected -> prepare (reason 'none') [30 40 0]
Mar 23 21:35:39 beast-vm-ubuntu NetworkManager[842]: <info> (tap0): device state change: prepare -> config (reason 'none') [40 50 0]
Mar 23 21:35:39 beast-vm-ubuntu NetworkManager[842]: <info> (tap0): device state change: config -> ip-config (reason 'none') [50 70 0]
Mar 23 21:35:39 beast-vm-ubuntu NetworkManager[842]: <info> (tap0): device state change: ip-config -> ip-check (reason 'none') [70 80 0]
Mar 23 21:35:39 beast-vm-ubuntu NetworkManager[842]: <info> (tap0): device state change: ip-check -> secondaries (reason 'none') [80 90 0]
Mar 23 21:35:39 beast-vm-ubuntu NetworkManager[842]: <info> (tap0): device state change: secondaries -> activated (reason 'none') [90 100 0]
Mar 23 21:35:39 beast-vm-ubuntu NetworkManager[842]: <info> (tap0): Activation: successful, device activated.
Mar 23 21:35:39 beast-vm-ubuntu nm-dispatcher: Dispatching action 'up' for tap0My routes before connecting to the VPN (I haven't modified them in any way):
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default router.asus.com 0.0.0.0 UG 100 0 0 enp0s3
link-local * 255.255.0.0 U 1000 0 0 enp0s3
192.168.1.0 * 255.255.255.0 U 100 0 0 enp0s3And after:
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default 192.168.1.1 0.0.0.0 UG 100 0 0 enp0s3
default 172.21.100.19 0.0.0.0 UG 950 0 0 tap0
77.88.79.74 192.168.1.1 255.255.255.255 UGH 0 0 0 enp0s3
link-local * 255.255.0.0 U 1000 0 0 enp0s3
172.21.100.0 * 255.255.255.0 U 0 0 0 tap0
192.168.1.0 * 255.255.255.0 U 100 0 0 enp0s3