Fix: Ping monitor crash when dns not configured

Source/NETworkManager.Models/Network/Ping.cs

@@ -10,7 +10,7 @@ namespace NETworkManager.Models.Network;
 
 public sealed class Ping
 {
-    #region Varaibles
+    #region Variables
 
     public int WaitTime = 1000;
     public int Timeout = 4000;

Source/NETworkManager.Utilities/DNSClient.cs

@@ -1,13 +1,17 @@
-using System.Collections.Generic;
+using DnsClient;
+using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Net;
 using System.Threading.Tasks;
-using DnsClient;
+using log4net;
 
 namespace NETworkManager.Utilities;
 
 public class DNSClient : SingletonBase<DNSClient>
 {
+    private static readonly ILog Log = LogManager.GetLogger(typeof(DNSClient));
+
     /// <summary>
     ///     Error message which is returned when the DNS client is not configured.
     /// </summary>
@@ -36,34 +40,41 @@ public void Configure(DNSClientSettings settings)
     {
         _settings = settings;
 
+        Log.Debug("Configuring DNS client...");
+
         if (_settings.UseCustomDNSServers)
         {
+            Log.Debug("Using custom DNS servers...");
+
             // Setup custom DNS servers
-            List<NameServer> servers = new();
+            List<NameServer> servers = [];
 
             foreach (var (server, port) in _settings.DNSServers)
+            {
+                Log.Debug($"Adding custom DNS server: {server}:{port}");
                 servers.Add(new IPEndPoint(IPAddress.Parse(server), port));
+            }
 
+            Log.Debug("Creating LookupClient with custom DNS servers...");
             _client = new LookupClient(new LookupClientOptions(servers.ToArray()));
         }
         else
         {
-            UpdateFromWindows();
+            Log.Debug("Creating LookupClient with Windows default DNS servers...");
+            _client = new LookupClient();
         }
-
+
+        Log.Debug("DNS client configured.");
         _isConfigured = true;
     }
 
     /// <summary>
     ///     Method to update the (Windows) name servers of the DNS client
     ///     when they may have changed due to a network update.
     /// </summary>
-    public void UpdateFromWindows()
+    public void UpdateWindowsDNSSever()
     {
-        // Default (Windows) settings
-        if (_settings.UseCustomDNSServers)
-            return;
-
+        Log.Debug("Recreating LookupClient with with Windows default DNS servers...");
         _client = new LookupClient();
     }
 
@@ -98,6 +109,11 @@ public async Task<DNSClientResultIPAddress> ResolveAAsync(string query)
         {
             return new DNSClientResultIPAddress(true, ex.Message);
         }
+        catch (Exception ex)
+        {
+            Log.Error($"Error while resolving A record (Query string is \"{query}\".", ex);
+            return new DNSClientResultIPAddress(true, ex.Message);
+        }
     }
 
     /// <summary>
@@ -131,6 +147,11 @@ public async Task<DNSClientResultIPAddress> ResolveAaaaAsync(string query)
         {
             return new DNSClientResultIPAddress(true, ex.Message);
         }
+        catch (Exception ex)
+        {
+            Log.Error($"Error while resolving AAAA record (Query string is \"{query}\".", ex);
+            return new DNSClientResultIPAddress(true, ex.Message);
+        }
     }
 
     /// <summary>
@@ -164,6 +185,11 @@ public async Task<DNSClientResultString> ResolveCnameAsync(string query)
         {
             return new DNSClientResultString(true, ex.Message);
         }
+        catch (Exception ex)
+        {
+            Log.Error($"Error while resolving CNAME record (Query string is \"{query}\".", ex);
+            return new DNSClientResultString(true, ex.Message);
+        }
     }
 
     /// <summary>
@@ -197,5 +223,10 @@ public async Task<DNSClientResultString> ResolvePtrAsync(IPAddress ipAddress)
         {
             return new DNSClientResultString(true, ex.Message);
         }
+        catch (Exception ex)
+        {
+            Log.Error($"Error while resolving PTR record (IP address is \"{ipAddress}\".", ex);
+            return new DNSClientResultString(true, ex.Message);
+        }
     }
-}
+}

Source/NETworkManager/MainWindow.xaml.cs

@@ -70,7 +70,7 @@ private void SettingsManager_PropertyChanged(object sender, PropertyChangedEvent
             // Update DNS server if changed in the settings
             case nameof(SettingsInfo.Network_UseCustomDNSServer):
             case nameof(SettingsInfo.Network_CustomDNSServer):
-                ConfigureDNS();
+                ConfigureDNSServer();
 
                 break;
 
@@ -466,8 +466,8 @@ public MainWindow()
         // Load and change appearance
         AppearanceManager.Load();
 
-        // Load and configure DNS
-        ConfigureDNS();
+        // Load and configure DNS server
+        ConfigureDNSServer();
 
         // Set window title
         Title = $"NETworkManager {AssemblyManager.Current.Version}";
@@ -1542,7 +1542,9 @@ private void ProfileManager_OnLoadedProfileFileChangedEvent(object sender, Profi
     private void CheckForUpdates()
     {
         var updater = new Updater();
+
         updater.UpdateAvailable += Updater_UpdateAvailable;
+
         updater.CheckOnGitHub(Properties.Resources.NETworkManager_GitHub_User,
             Properties.Resources.NETworkManager_GitHub_Repo, AssemblyManager.Current.Version,
             SettingsManager.Current.Update_CheckForPreReleases);
@@ -1873,9 +1875,9 @@ private void BringWindowToFront()
         Activate();
     }
 
-    private void ConfigureDNS()
+    private void ConfigureDNSServer()
     {
-        Log.Info("Configure application DNS...");
+        Log.Info("Configure application DNS servers...");
 
         DNSClientSettings dnsSettings = new();
 
@@ -1885,41 +1887,33 @@ private void ConfigureDNS()
             {
                 Log.Info($"Use custom DNS servers ({SettingsManager.Current.Network_CustomDNSServer})...");
 
-                List<(string Server, int Port)> dnsServers = new();
-
-                foreach (var dnsServer in SettingsManager.Current.Network_CustomDNSServer.Split(";"))
-                    dnsServers.Add((dnsServer, 53));
+                List<(string Server, int Port)> dnsServers = SettingsManager.Current.Network_CustomDNSServer.Split(";")
+                    .Select(dnsServer => (dnsServer, 53))
+                    .ToList();
 
                 dnsSettings.UseCustomDNSServers = true;
                 dnsSettings.DNSServers = dnsServers;
             }
             else
             {
                 Log.Info(
-                    $"Custom DNS servers could not be set (Setting \"{nameof(SettingsManager.Current.Network_CustomDNSServer)}\" has value \"{SettingsManager.Current.Network_CustomDNSServer}\")! Fallback to Windows DNS servers...");
+                    $"Custom DNS servers could not be set (Setting \"{nameof(SettingsManager.Current.Network_CustomDNSServer)}\" has value \"{SettingsManager.Current.Network_CustomDNSServer}\")! Fallback to Windows default DNS servers...");
             }
         }
         else
         {
-            Log.Info("Use Windows DNS servers...");
+            Log.Info("Use Windows default DNS servers...");
         }
 
         DNSClient.GetInstance().Configure(dnsSettings);
     }
 
-    private void UpdateDNS()
-    {
-        Log.Info("Update Windows DNS servers...");
-
-        DNSClient.GetInstance().UpdateFromWindows();
-    }
-
     private void WriteDefaultPowerShellProfileToRegistry()
     {
         if (!SettingsManager.Current.Appearance_PowerShellModifyGlobalProfile)
             return;
 
-        HashSet<string> paths = new();
+        HashSet<string> paths = [];
 
         // PowerShell
         if (!string.IsNullOrEmpty(SettingsManager.Current.PowerShell_ApplicationFilePath) &&
@@ -1958,12 +1952,20 @@ private async void OnNetworkHasChanged()
 
         // Update DNS server if network changed
         if (!SettingsManager.Current.Network_UseCustomDNSServer)
-            UpdateDNS();
+        {
+            Log.Info("Update Windows default DNS servers...");
+            DNSClient.GetInstance().UpdateWindowsDNSSever();
+        }
 
         // Show status window on network change
         if (SettingsManager.Current.Status_ShowWindowOnNetworkChange)
-            await Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action(delegate { OpenStatusWindow(true); }));
-
+        {
+            await Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action(delegate
+            {
+                OpenStatusWindow(true);
+            }));
+        }
+
         _isNetworkChanging = false;
     }
 

Website/docs/changelog/next-release.md

@@ -30,6 +30,9 @@ Release date: **xx.xx.2024**
 
 ## Bugfixes
 
+- **Ping Monitor**
+  - A problem has been fixed where the ping does not start if the DNS server is not configured. This can occur if the network interface via which the Windows DNS server was configured is deactivated/disconnected. [#2876](https://github.com/BornToBeRoot/NETworkManager/pull/2876)
+
 - TextBox content not centered because of ScrollViewer issue. [#2763](https://github.com/BornToBeRoot/NETworkManager/pull/2763)
 
 ## Dependencies, Refactoring & Documentation