CODEWITHSUNDEEP
windowsdockervpn
Aleksei Petrov
Aleksei Petrov

Reputation: 1099

Docker Desktop Windows and VPN - no network connection inside container

I'm trying to use Docker on Windows while being connected to VPN.

When VPN is not connected, everything works OK.

But when I connect to our corporate VPN using Cisco AnyConnect client, network inside docker container is not working anymore:

docker run alpine ping www.google.com
ping: bad address 'www.google.com'

docker run alpine ping -c 5 216.58.204.36
PING 216.58.204.36 (216.58.204.36): 56 data bytes
--- 216.58.204.36 ping statistics ---
5 packets transmitted, 0 packets received, 100% packet loss

How to fix this issue and make it work?

My setup is:

Upvotes: 9

Views: 9780

Answers (2)

bantal
bantal

Reputation: 43

While my VPN (AnyConnect) was running, I had to run the following from PowerShell (admin mode):

Get-NetAdapter | Where-Object {$_.InterfaceDescription -Match "Cisco AnyConnect"} | Set-NetIPInterface -InterfaceMetric 6000

Upvotes: 3

Kendar
Kendar

Reputation: 710

Actually i did it using Docker Desktop and Hyper-V virtual machines. Using OpenConnect but i think it can be done for most VPN client with minor adaptations.

The fully explained instructions are here Docker Desktop, Hyper-V and VPN with the settings for Docker containers, Windows VMs and Linux VMs

  • I created a new internal Virtual Switch (let's call it "Internal") and assigned to it a static IP address (let's say 192.168.4.2)

  • I created a new VM with Ubuntu server and OpenConnect, connected to both the default Virtual Switch and the "Internal"

  • On the OpenConnect VM

    • Assigned to "Internal" a fixed ip (192.168.4.3)

    • Added a new tun interface "persistent" telling openconnect to use that tun (adding the "-i tun0" parameter as openconnect start parameter)

      sudo ip tuntap add name tun0 mode tun

    • Installed the persist-iptables

    • Forced the ip forwarding

      sudo echo "net.ipv4.ip_forward=1" >> /etc/sysctl.conf && sysctl -p

    • Setup the routing

      sudo iptables -t nat -A POSTROUTING -o tun0 -j MASQUERADE sudo iptables -A FORWARD -i eth0 -o tun0 -j ACCEPT sudo iptables -A FORWARD -o tun0 -j ACCEPT sudo iptables -A FORWARD -i tun0 -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT sudo iptables -A INPUT -i tun0 -j ACCEPT

    • After connecting the vpn i added permanently the dns servers to the resolve.conf

    • And retrieve the class of addresses of the VPN (like 10...* )

  • On the Docker containers

    • Added on Dockerfile the basic route

      RUN route add -net 10.0.0.0 netmask 255.0.0.0 gw 192.168.4.3

    • Then running the docker file i added the dns giving net admin and sys module permissions

      --dns 8.8.8.8 --dns 10.1.77.21 --dns 10.4.52.21 --dns-search test.dns.it
      --cap-add=NET_ADMIN --cap-add=SYS_MODULE

Upvotes: 0

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