mirror of
https://github.com/fergalmoran/DnsServer.git
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DropRequestsApp: added new app
This commit is contained in:
Shreyas Zare
192
Apps/DropRequestsApp/App.cs
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192
Apps/DropRequestsApp/App.cs
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/*
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Technitium DNS Server
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Copyright (C) 2021 Shreyas Zare (shreyas@technitium.com)
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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using DnsApplicationCommon;
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using Newtonsoft.Json;
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using System;
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using System.Collections.Generic;
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using System.Net;
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using System.Threading.Tasks;
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using TechnitiumLibrary.Net;
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using TechnitiumLibrary.Net.Dns;
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namespace DropRequests
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{
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public class App : IDnsRequestController
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{
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#region variables
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bool _enableBlocking;
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IReadOnlyList<NetworkAddress> _allowedNetworks;
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IReadOnlyList<NetworkAddress> _blockedNetworks;
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IReadOnlyList<BlockedQuestion> _blockedQuestions;
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#endregion
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#region IDisposable
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public void Dispose()
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{
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//do nothing
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}
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#endregion
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#region public
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public Task InitializeAsync(IDnsServer dnsServer, string config)
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{
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dynamic jsonConfig = JsonConvert.DeserializeObject(config);
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_enableBlocking = jsonConfig.enableBlocking.Value;
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if (jsonConfig.allowedNetworks is null)
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{
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_allowedNetworks = Array.Empty<NetworkAddress>();
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}
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else
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{
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List<NetworkAddress> allowedNetworks = new List<NetworkAddress>();
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foreach (dynamic allowedNetwork in jsonConfig.allowedNetworks)
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{
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allowedNetworks.Add(NetworkAddress.Parse(allowedNetwork.Value));
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}
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_allowedNetworks = allowedNetworks;
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}
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if (jsonConfig.blockedNetworks is null)
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{
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_blockedNetworks = Array.Empty<NetworkAddress>();
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}
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else
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{
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List<NetworkAddress> blockedNetworks = new List<NetworkAddress>();
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foreach (dynamic blockedNetwork in jsonConfig.blockedNetworks)
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{
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blockedNetworks.Add(NetworkAddress.Parse(blockedNetwork.Value));
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}
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_blockedNetworks = blockedNetworks;
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}
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if (jsonConfig.blockedQuestions is null)
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{
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_blockedQuestions = Array.Empty<BlockedQuestion>();
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}
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else
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{
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List<BlockedQuestion> blockedQuestions = new List<BlockedQuestion>();
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foreach (dynamic blockedQuestion in jsonConfig.blockedQuestions)
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{
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blockedQuestions.Add(new BlockedQuestion(blockedQuestion));
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}
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_blockedQuestions = blockedQuestions;
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}
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return Task.CompletedTask;
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}
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public Task<DnsRequestControllerAction> GetRequestActionAsync(DnsDatagram request, IPEndPoint remoteEP, DnsTransportProtocol protocol)
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{
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if (!_enableBlocking)
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return Task.FromResult(DnsRequestControllerAction.Allow);
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IPAddress remoteIp = remoteEP.Address;
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foreach (NetworkAddress allowedNetwork in _allowedNetworks)
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{
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if (allowedNetwork.Contains(remoteIp))
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return Task.FromResult(DnsRequestControllerAction.Allow);
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}
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foreach (NetworkAddress blockedNetwork in _blockedNetworks)
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{
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if (blockedNetwork.Contains(remoteIp))
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return Task.FromResult(DnsRequestControllerAction.DropSilently);
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}
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if (request.Question.Count != 1)
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return Task.FromResult(DnsRequestControllerAction.DropSilently);
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DnsQuestionRecord requestQuestion = request.Question[0];
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foreach (BlockedQuestion blockedQuestion in _blockedQuestions)
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{
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if (blockedQuestion.Matches(requestQuestion))
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return Task.FromResult(DnsRequestControllerAction.DropSilently);
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}
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return Task.FromResult(DnsRequestControllerAction.Allow);
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}
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#endregion
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#region properties
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public string Description
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{ get { return "Drop incoming DNS requests that match the rules in the config."; } }
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#endregion
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class BlockedQuestion
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{
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#region variables
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readonly string _name;
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readonly DnsResourceRecordType _type;
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#endregion
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#region constructor
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public BlockedQuestion(dynamic jsonQuestion)
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{
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_name = jsonQuestion.name?.Value;
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string strType = jsonQuestion.type?.Value;
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if (!string.IsNullOrEmpty(strType) && Enum.TryParse(strType, true, out DnsResourceRecordType type))
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_type = type;
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else
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_type = DnsResourceRecordType.Unknown;
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}
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#endregion
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#region public
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public bool Matches(DnsQuestionRecord question)
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{
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if ((_name is not null) && !_name.Equals(question.Name, StringComparison.OrdinalIgnoreCase))
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return false;
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if ((_type != DnsResourceRecordType.Unknown) && (_type != question.Type))
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return false;
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return true;
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}
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#endregion
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}
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}
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}
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41
Apps/DropRequestsApp/DropRequestsApp.csproj
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41
Apps/DropRequestsApp/DropRequestsApp.csproj
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<Project Sdk="Microsoft.NET.Sdk">
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<PropertyGroup>
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<TargetFramework>net5.0</TargetFramework>
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<AppendTargetFrameworkToOutputPath>false</AppendTargetFrameworkToOutputPath>
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<Version>1.0</Version>
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<Company>Technitium</Company>
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<Product>Technitium DNS Server</Product>
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<Authors>Shreyas Zare</Authors>
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<AssemblyName>DropRequestsApp</AssemblyName>
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<RootNamespace>DropRequests</RootNamespace>
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<PackageProjectUrl>https://technitium.com/dns/</PackageProjectUrl>
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<RepositoryUrl>https://github.com/TechnitiumSoftware/DnsServer</RepositoryUrl>
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<GeneratePackageOnBuild>false</GeneratePackageOnBuild>
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<OutputType>Library</OutputType>
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</PropertyGroup>
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<ItemGroup>
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<PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
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</ItemGroup>
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<ItemGroup>
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<ProjectReference Include="..\..\DnsApplicationCommon\DnsApplicationCommon.csproj">
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<Private>false</Private>
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</ProjectReference>
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</ItemGroup>
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<ItemGroup>
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<Reference Include="TechnitiumLibrary.Net">
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<HintPath>..\..\..\TechnitiumLibrary\bin\TechnitiumLibrary.Net.dll</HintPath>
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<Private>false</Private>
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</Reference>
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</ItemGroup>
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<ItemGroup>
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<None Update="dnsApp.config">
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<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
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</None>
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</ItemGroup>
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</Project>
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33
Apps/DropRequestsApp/dnsApp.config
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33
Apps/DropRequestsApp/dnsApp.config
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@@ -0,0 +1,33 @@
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{
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"enableBlocking": true,
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"allowedNetworks": [
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"127.0.0.1",
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"::1",
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"10.0.0.0/8",
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"172.16.0.0/12",
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"192.168.0.0/16"
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],
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"blockedNetworks": [
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"1.1.1.1/24"
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],
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"blockedQuestions": [
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{
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"name": "example.com"
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},
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{
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"type": "ANY"
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},
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{
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"name": "pizzaseo.com",
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"type": "RRSIG"
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},
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{
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"name": "sl",
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"type": "ANY"
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},
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{
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"name": "a.a.a.ooooops.space",
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"type": "A"
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}
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]
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}
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