microsoft / primedns

PrimeDNS is a DNS caching service that helps the user to continually maintain last known good DNS resolutions in the system's hostfile. It has been implemented in C# using dotnet core framework.

PrimeDNS: An Automated DNS Resiliency Provider

PrimeDNS is a DNS caching service that helps the user to continually maintain last known good DNS resolutions in the system's hostfile. It has been implemented in C# using dotnet core framework.

Getting Started

1. For running PrimeDNS locally:
   • Clone this repository to your local drive
   • If you don’t have dotnet installed, you can install it here - https://www.microsoft.com/net/download/thank-you/dotnet-runtime-2.1.0-windows-hosting-bundle-installer
   • Once installed, run the following commands

      cd PrimeDNS\PrimeDNS
      dotnet publish --runtime win10-x86
     

   • This will create a folder \PrimeDNS\PrimeDNS\bin\Debug\netcoreapp2.1\win10-x86 containing the executables needed to run PrimeDNS.

Configure PrimeDNS to suit your purpose

1. AppSettings.json

   • The folder 'win10-x86' you created contains template AppSettings.json that you should edit to suit your needs.
   • Telemetry options are by default set to false
   • Currently, TTL Updater isn't fully functional, so keep that option as false.

2. Domains.json

   • The folder 'win10-x86' you created contains template Domains.json that you should use to add the domains of interest to you.

3. Data Folder Location

   • The default data (config files) folder is the folder containing PrimeDNS executables.
   • But PrimeDNS provides you the facility to separate your data folder and we highly recommend that you create a separate data folder.
   • To do this copy the Files folder from PrimeDNS\PrimeDNS and paste it into any location that suits you, let's call this location -

      <primednsdata>
     

   • Now, edit the AppSettings.json and Domains.json file in this newly created Files folder as suggested above.
   • Once this is done, you can run PrimeDNS by using the following command

      primedns.exe <primednsdata>
     

   • This will help your team to maintain your own personalized config files that won't get overwritten with every update to PrimeDNS.

Important

Once you stop PrimeDns from running, you need to clear the PrimeDns section from hosts file as otherwise the last PrimeDns section written to your hosts will remain there forever! 😶

Contributing

Hi there 😊

We're thrilled that you'd like to contribute to this project. Your help is essential for taking PrimeDNS forward!

This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.opensource.microsoft.com.

When you submit a pull request, a CLA bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., status check, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repos using our CLA.

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact [email protected] with any additional questions or comments.

How can you help?

Currently, we have identified 3 main bugs/enhancements where we are looking for help from awesome people like you -

1. TTL Updater is not functional We would ideally like PrimeDNS to query the authoritative nameservers and update the domain's TTL once in say few hours. Currently, this part of the code is disfunctional and so a default TTL of 300 is assumed for all domains.
2. HostfileUpdater: Should Update only when there is a change that needs updating. Only recently did we realize that whenever hostfile is edited, local DNS cache gets flushed 😟 This means,
   1. We should minimalize the number of edits to hostfile to the best we can.
   2. We should dynamically detect the critical domains list (instead of a static input list) so that PrimeDNS can take care of the top few hundred domains without affecting the cache or latency of any.
3. Dynamic Detection of Input Domains To those looking to solve something new and interesting, this might be a great place to start! We want to figure out how to dynamically identify the critical domains list for any PC at any given time and then be able to make that a part of PrimeDNS by making the code dotnet core compatible. Isn't this exciting?

Contact

As we can see, PrimeDNS needs a lot more work to become really useful and so thank you for coming forward to help ☺️

primedns's Issues

HostfileUpdater: Should Update only when there is a change that needs updating.

Currently hostfile updater updates every 60 seconds (or fixed time period) which is not a good design given touching the hostfile clears the local DNS caches. Hence, we would like to make it update only when there is a change that needs updating.

Code and Comment Enhancements

The code needs some standardization and better commenting.

Update DnsClient.NET to 1.3.0

DnsClient.NET has an issue that is affecting PrimeDNS as well. Hence, we need to update to version 1.3.0 to get it working - MichaCo/DnsClient.NET#55

TTL Updater is not functional

TTL updater is not currently functional. The code needs to be improved and completed.

Dynamic Detection of Input Domains

Currently, PrimeDNS takes a list of domain names given by the user as it's input. This process should be made dynamic in future as -

1. The user might not know which domains are critical to them.
2. Whenever PrimeDNS edits the hostfile, it clears the local dns caches. Hence, we need to provide caching for all important domains.
3. PrimeDNS already has the ability to watch the domains.json file periodically and look for any updates.