https://github.com/stephbu/csharp-dns-server
Fully functional DNS server written in C#
https://github.com/stephbu/csharp-dns-server
Last synced: 22 days ago
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Fully functional DNS server written in C#
- Host: GitHub
- URL: https://github.com/stephbu/csharp-dns-server
- Owner: stephbu
- License: mit
- Created: 2015-05-22T19:00:48.000Z (almost 10 years ago)
- Default Branch: master
- Last Pushed: 2024-03-05T04:22:54.000Z (about 1 year ago)
- Last Synced: 2024-10-29T03:32:16.376Z (6 months ago)
- Language: C#
- Homepage:
- Size: 131 KB
- Stars: 109
- Watchers: 3
- Forks: 29
- Open Issues: 16
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Metadata Files:
- Readme: README.md
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README
# csharp-dns-server
Fully functional DNS server written in C#.
The project was conceived while working to reduce the cost of datacentre "stamps" while providing robust services within a datacentre, specifically to remove the need for an expensive load-balancer device by providing round-robin DNS services, and retrying connectivity instead.
## Licence
This software is licenced under MIT terms that permits reuse within proprietary software provided all copies of the licensed software include a copy of the MIT License terms and the copyright notice. See [licence.txt](./licence.txt)
## Getting Started
```
// clone the repo
>> cd $repo-root
>> git clone https://github.com/stephbu/csharp-dns-server
// check you can build the project
>> cd $repo-root/csharp-dns-server
>> dotnet build
// check that the tests run
>> dotnet test
```
## Gotchas
- if you're running on Windows 10 with Docker Tools installed, Docker uses the ICS SharedAccess service to provide DNS resolution for Docker containers - this listens on UDP:53, and will conflict with the DNS project. Either turn off the the service (```net stop SharedAccess```), or change the UDP port.
## Features
As written, the server has the following features:
- Pluggable Zone Resolver. Host one or more zones locally, and run your code to resolve names in that zone. Enables many complex scenarios such as:
- round-robin load-balancing. Distribute load and provide failover with a datacentre without expensive hardware.
- health-checks. While maintaining a list of machines in round-robin for a name, the code performs periodic healthchecks against the machines, if necessary removing machines that fail the health checks from rotation.
- Delegates all other DNS lookup to host machines default DNS server(s)
The DNS server has a built-in Web Server providing operational insight into the current server behaviour.
- healthcheck for server status
- counters
- zone information
## Interesting Possible Uses
Time-based constraints such as parental controls to block a site, e.g. Facebook.
Logging of site usage e.g. company notifications
## Challenges
### Testing
Two phases of testing was completed.
1) Verification that the bit-packing classes correctly added and removed bits in correct Endian order, complicated by network bitpacking in reverse order to Windows big-endian packing.
2) Protocol verification - that well known messages were correctly decoded and re-encoded using the bit-packing system.
Much time was spent using Netmon to capture real DNS challenges and verify that the C# DNS server responded appropriately.
### DNS-Sec
No effort made to handle or respond to DNS-Sec challenges.
## Contribution Guide
Pull Requests, Bug Reports, and Feature Requests are most welcome.
### Contribution Workflow
Suggested workflow for PRs is
1. Make a fork of csharp-dns-server/master in your own repository.
2. Create a branch in your own repo to entirely encapsulate all your proposed changes
3. Make your changes, add documentation if you need it, markdown text preferred.
4. Squash your commits into a single change [(Find out how to squash here)](http://stackoverflow.com/questions/616556/how-do-you-squash-commits-into-one-patch-with-git-format-patch)
5. Submit a PR, and put in comments anything that you think I'll need to help merge and evaluate the changes
### Licence Reminder
All contributions must be licenced under the same MIT terms, do include a header file to that effect.