Cloud DNS with OpenVPN not resolving on client












-1














I'm trying to use Google Cloud Platform's Cloud DNS to resolve internal IPs of Compute Engine instances by DNS from my local machine. I was able to setup an OpenVPN server on an instance by following this guide: https://www.digitalocean.com/community/tutorials/how-to-set-up-an-openvpn-server-on-ubuntu-16-04



My VPN configuration successfully connects to the OpenVPN server, and allows me to ping internal IPs of my GCE instances. The instance hosting my OpenVPN server is able to resolve and ping cloud DNS entries, but my client local machine is unable to do the same.



Here's the content of my /etc/resolve.conf file after connecting to the VPN server.



search openvpn
nameserver 169.254.169.254


What additional configuration do I need to do to allow my local machine to resolve Cloud DNS addresses?










share|improve this question






















  • I have not verified this but I do not believe that you can reach the internal DNS server from outside the VPC. What you are trying to configure is split-brain DNS resolution. From you desktop: dig www.google.com 169.254.169.254 or nslookup www.google.com 169.254.169.254. If this fails that my assumption is correct. In that case you would need to setup a DNS server inside your VPC and then point your nameserver to that server's IP.
    – John Hanley
    Nov 20 at 17:50












  • Tip: I run into this situation often with customers. I wrote a simple python program that dumps the internal DNS server's entries to a file. I then use that file for my local machine's host configuration. Not good for production use but does the job for my local machine's VPN connection.
    – John Hanley
    Nov 20 at 17:54


















-1














I'm trying to use Google Cloud Platform's Cloud DNS to resolve internal IPs of Compute Engine instances by DNS from my local machine. I was able to setup an OpenVPN server on an instance by following this guide: https://www.digitalocean.com/community/tutorials/how-to-set-up-an-openvpn-server-on-ubuntu-16-04



My VPN configuration successfully connects to the OpenVPN server, and allows me to ping internal IPs of my GCE instances. The instance hosting my OpenVPN server is able to resolve and ping cloud DNS entries, but my client local machine is unable to do the same.



Here's the content of my /etc/resolve.conf file after connecting to the VPN server.



search openvpn
nameserver 169.254.169.254


What additional configuration do I need to do to allow my local machine to resolve Cloud DNS addresses?










share|improve this question






















  • I have not verified this but I do not believe that you can reach the internal DNS server from outside the VPC. What you are trying to configure is split-brain DNS resolution. From you desktop: dig www.google.com 169.254.169.254 or nslookup www.google.com 169.254.169.254. If this fails that my assumption is correct. In that case you would need to setup a DNS server inside your VPC and then point your nameserver to that server's IP.
    – John Hanley
    Nov 20 at 17:50












  • Tip: I run into this situation often with customers. I wrote a simple python program that dumps the internal DNS server's entries to a file. I then use that file for my local machine's host configuration. Not good for production use but does the job for my local machine's VPN connection.
    – John Hanley
    Nov 20 at 17:54
















-1












-1








-1







I'm trying to use Google Cloud Platform's Cloud DNS to resolve internal IPs of Compute Engine instances by DNS from my local machine. I was able to setup an OpenVPN server on an instance by following this guide: https://www.digitalocean.com/community/tutorials/how-to-set-up-an-openvpn-server-on-ubuntu-16-04



My VPN configuration successfully connects to the OpenVPN server, and allows me to ping internal IPs of my GCE instances. The instance hosting my OpenVPN server is able to resolve and ping cloud DNS entries, but my client local machine is unable to do the same.



Here's the content of my /etc/resolve.conf file after connecting to the VPN server.



search openvpn
nameserver 169.254.169.254


What additional configuration do I need to do to allow my local machine to resolve Cloud DNS addresses?










share|improve this question













I'm trying to use Google Cloud Platform's Cloud DNS to resolve internal IPs of Compute Engine instances by DNS from my local machine. I was able to setup an OpenVPN server on an instance by following this guide: https://www.digitalocean.com/community/tutorials/how-to-set-up-an-openvpn-server-on-ubuntu-16-04



My VPN configuration successfully connects to the OpenVPN server, and allows me to ping internal IPs of my GCE instances. The instance hosting my OpenVPN server is able to resolve and ping cloud DNS entries, but my client local machine is unable to do the same.



Here's the content of my /etc/resolve.conf file after connecting to the VPN server.



search openvpn
nameserver 169.254.169.254


What additional configuration do I need to do to allow my local machine to resolve Cloud DNS addresses?







dns google-cloud-platform vpn openvpn google-cloud-dns






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Nov 20 at 16:33









Jacob Smith

14




14












  • I have not verified this but I do not believe that you can reach the internal DNS server from outside the VPC. What you are trying to configure is split-brain DNS resolution. From you desktop: dig www.google.com 169.254.169.254 or nslookup www.google.com 169.254.169.254. If this fails that my assumption is correct. In that case you would need to setup a DNS server inside your VPC and then point your nameserver to that server's IP.
    – John Hanley
    Nov 20 at 17:50












  • Tip: I run into this situation often with customers. I wrote a simple python program that dumps the internal DNS server's entries to a file. I then use that file for my local machine's host configuration. Not good for production use but does the job for my local machine's VPN connection.
    – John Hanley
    Nov 20 at 17:54




















  • I have not verified this but I do not believe that you can reach the internal DNS server from outside the VPC. What you are trying to configure is split-brain DNS resolution. From you desktop: dig www.google.com 169.254.169.254 or nslookup www.google.com 169.254.169.254. If this fails that my assumption is correct. In that case you would need to setup a DNS server inside your VPC and then point your nameserver to that server's IP.
    – John Hanley
    Nov 20 at 17:50












  • Tip: I run into this situation often with customers. I wrote a simple python program that dumps the internal DNS server's entries to a file. I then use that file for my local machine's host configuration. Not good for production use but does the job for my local machine's VPN connection.
    – John Hanley
    Nov 20 at 17:54


















I have not verified this but I do not believe that you can reach the internal DNS server from outside the VPC. What you are trying to configure is split-brain DNS resolution. From you desktop: dig www.google.com 169.254.169.254 or nslookup www.google.com 169.254.169.254. If this fails that my assumption is correct. In that case you would need to setup a DNS server inside your VPC and then point your nameserver to that server's IP.
– John Hanley
Nov 20 at 17:50






I have not verified this but I do not believe that you can reach the internal DNS server from outside the VPC. What you are trying to configure is split-brain DNS resolution. From you desktop: dig www.google.com 169.254.169.254 or nslookup www.google.com 169.254.169.254. If this fails that my assumption is correct. In that case you would need to setup a DNS server inside your VPC and then point your nameserver to that server's IP.
– John Hanley
Nov 20 at 17:50














Tip: I run into this situation often with customers. I wrote a simple python program that dumps the internal DNS server's entries to a file. I then use that file for my local machine's host configuration. Not good for production use but does the job for my local machine's VPN connection.
– John Hanley
Nov 20 at 17:54






Tip: I run into this situation often with customers. I wrote a simple python program that dumps the internal DNS server's entries to a file. I then use that file for my local machine's host configuration. Not good for production use but does the job for my local machine's VPN connection.
– John Hanley
Nov 20 at 17:54














1 Answer
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In Compute Engine, DNS resolution is performed against the metadata server, which always has IP 169.254.169.254. The issue arises from the fact that this IP is link-local and is non-routable, thus will not work over VPN/IPSEC.



There are a few solutions/workarounds for it:




  1. You could map all internal GCE instances IPs in the hosts files of the servers in your private network - the drawback is that the process is manual and time-consuming depending on how many instances you have.


  2. The second option would be an internal GCE server (internal resolver) running a DNS server which could cross networks. More information on this is available in this documentation.







share|improve this answer





















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    In Compute Engine, DNS resolution is performed against the metadata server, which always has IP 169.254.169.254. The issue arises from the fact that this IP is link-local and is non-routable, thus will not work over VPN/IPSEC.



    There are a few solutions/workarounds for it:




    1. You could map all internal GCE instances IPs in the hosts files of the servers in your private network - the drawback is that the process is manual and time-consuming depending on how many instances you have.


    2. The second option would be an internal GCE server (internal resolver) running a DNS server which could cross networks. More information on this is available in this documentation.







    share|improve this answer


























      0














      In Compute Engine, DNS resolution is performed against the metadata server, which always has IP 169.254.169.254. The issue arises from the fact that this IP is link-local and is non-routable, thus will not work over VPN/IPSEC.



      There are a few solutions/workarounds for it:




      1. You could map all internal GCE instances IPs in the hosts files of the servers in your private network - the drawback is that the process is manual and time-consuming depending on how many instances you have.


      2. The second option would be an internal GCE server (internal resolver) running a DNS server which could cross networks. More information on this is available in this documentation.







      share|improve this answer
























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        0






        In Compute Engine, DNS resolution is performed against the metadata server, which always has IP 169.254.169.254. The issue arises from the fact that this IP is link-local and is non-routable, thus will not work over VPN/IPSEC.



        There are a few solutions/workarounds for it:




        1. You could map all internal GCE instances IPs in the hosts files of the servers in your private network - the drawback is that the process is manual and time-consuming depending on how many instances you have.


        2. The second option would be an internal GCE server (internal resolver) running a DNS server which could cross networks. More information on this is available in this documentation.







        share|improve this answer












        In Compute Engine, DNS resolution is performed against the metadata server, which always has IP 169.254.169.254. The issue arises from the fact that this IP is link-local and is non-routable, thus will not work over VPN/IPSEC.



        There are a few solutions/workarounds for it:




        1. You could map all internal GCE instances IPs in the hosts files of the servers in your private network - the drawback is that the process is manual and time-consuming depending on how many instances you have.


        2. The second option would be an internal GCE server (internal resolver) running a DNS server which could cross networks. More information on this is available in this documentation.








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        share|improve this answer










        answered Nov 21 at 22:01









        Md Zubayer

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