diff --git a/v2rayN/ServiceLib/Handler/ConnectionHandler.cs b/v2rayN/ServiceLib/Handler/ConnectionHandler.cs
index 05825d93..6fd7d453 100644
--- a/v2rayN/ServiceLib/Handler/ConnectionHandler.cs
+++ b/v2rayN/ServiceLib/Handler/ConnectionHandler.cs
@@ -4,6 +4,9 @@ public static class ConnectionHandler
 {
     private static readonly string _tag = "ConnectionHandler";
 
+    /// <summary>
+    /// Runs ping and IP checks and returns a formatted result string.
+    /// </summary>
     public static async Task<string> RunAvailabilityCheck()
     {
         var time = await GetRealPingTimeInfo();
@@ -12,40 +15,24 @@ public static class ConnectionHandler
         return string.Format(ResUI.TestMeOutput, time, ip);
     }
 
+    /// <summary>
+    /// Gets IP information using the default local proxy.
+    /// </summary>
     private static async Task<string?> GetIPInfo()
     {
-        var url = AppManager.Instance.Config.SpeedTestItem.IPAPIUrl;
-        if (url.IsNullOrEmpty())
-        {
-            return null;
-        }
-
-        var downloadHandle = new DownloadService();
-        var result = await downloadHandle.TryDownloadString(url, true, "");
-        if (result == null)
-        {
-            return null;
-        }
-
-        var ipInfo = JsonUtils.Deserialize<IPAPIInfo>(result);
-        if (ipInfo == null)
-        {
-            return null;
-        }
-
-        var ip = ipInfo.ip ?? ipInfo.clientIp ?? ipInfo.ip_addr ?? ipInfo.query;
-        var country = ipInfo.country_code ?? ipInfo.country ?? ipInfo.countryCode ?? ipInfo.location?.country_code;
-
-        return $"({country ?? "unknown"}) {ip}";
+        var webProxy = await GetWebProxy();
+        return await GetIPInfo(webProxy);
     }
 
+    /// <summary>
+    /// Measures real ping time using configured test URL.
+    /// </summary>
     private static async Task<int> GetRealPingTimeInfo()
     {
         var responseTime = -1;
         try
         {
-            var port = AppManager.Instance.GetLocalPort(EInboundProtocol.socks);
-            var webProxy = new WebProxy($"socks5://{Global.Loopback}:{port}");
+            var webProxy = await GetWebProxy();
             var url = AppManager.Instance.Config.SpeedTestItem.SpeedPingTestUrl;
 
             for (var i = 0; i < 2; i++)
@@ -66,6 +53,18 @@ public static class ConnectionHandler
         return responseTime;
     }
 
+    /// <summary>
+    /// Creates local SOCKS proxy instance.
+    /// </summary>
+    private static async Task<WebProxy?> GetWebProxy()
+    {
+        var port = AppManager.Instance.GetLocalPort(EInboundProtocol.socks);
+        return new WebProxy($"socks5://{Global.Loopback}:{port}");
+    }
+
+    /// <summary>
+    /// Measures response time by sending HTTP requests through proxy.
+    /// </summary>
     public static async Task<int> GetRealPingTime(string url, IWebProxy? webProxy, int downloadTimeout)
     {
         var responseTime = -1;
@@ -95,4 +94,34 @@ public static class ConnectionHandler
         }
         return responseTime;
     }
+
+    /// <summary>
+    /// Gets IP and country information through specified proxy.
+    /// </summary>
+    public static async Task<string?> GetIPInfo(IWebProxy? webProxy)
+    {
+        var url = AppManager.Instance.Config.SpeedTestItem.IPAPIUrl;
+        if (url.IsNullOrEmpty())
+        {
+            return null;
+        }
+
+        var downloadHandle = new DownloadService();
+        var result = await downloadHandle.TryDownloadString(url, webProxy, "");
+        if (result == null)
+        {
+            return null;
+        }
+
+        var ipInfo = JsonUtils.Deserialize<IPAPIInfo>(result);
+        if (ipInfo == null)
+        {
+            return null;
+        }
+
+        var ip = ipInfo.ip ?? ipInfo.clientIp ?? ipInfo.ip_addr ?? ipInfo.query;
+        var country = ipInfo.country_code ?? ipInfo.country ?? ipInfo.countryCode ?? ipInfo.location?.country_code;
+
+        return $"({country ?? "unknown"}) {ip}";
+    }
 }
diff --git a/v2rayN/ServiceLib/Services/DownloadService.cs b/v2rayN/ServiceLib/Services/DownloadService.cs
index 77d3a7c1..1dbdfae2 100644
--- a/v2rayN/ServiceLib/Services/DownloadService.cs
+++ b/v2rayN/ServiceLib/Services/DownloadService.cs
@@ -3,7 +3,7 @@ using System.Net.Http.Headers;
 namespace ServiceLib.Services;
 
 /// <summary>
-///Download
+/// Download
 /// </summary>
 public class DownloadService
 {
@@ -13,7 +13,10 @@ public class DownloadService
 
     private static readonly string _tag = "DownloadService";
 
-    public async Task<int> DownloadDataAsync(string url, WebProxy webProxy, int downloadTimeout, Func<bool, string, Task> updateFunc)
+    /// <summary>
+    /// Downloads data with the specified proxy and reports progress messages.
+    /// </summary>
+    public async Task<int> DownloadDataAsync(string url, IWebProxy webProxy, int downloadTimeout, Func<bool, string, Task> updateFunc)
     {
         try
         {
@@ -36,6 +39,9 @@ public class DownloadService
         return 0;
     }
 
+    /// <summary>
+    /// Downloads a file and reports progress through events.
+    /// </summary>
     public async Task DownloadFileAsync(string url, string fileName, bool blProxy, int downloadTimeout)
     {
         try
@@ -64,6 +70,9 @@ public class DownloadService
         }
     }
 
+    /// <summary>
+    /// Gets redirect target URL without following redirects automatically.
+    /// </summary>
     public async Task<string?> UrlRedirectAsync(string url, bool blProxy)
     {
         var webRequestHandler = new SocketsHttpHandler
@@ -86,11 +95,23 @@ public class DownloadService
         }
     }
 
+    /// <summary>
+    /// Tries to download string content using proxy switch setting.
+    /// </summary>
     public async Task<string?> TryDownloadString(string url, bool blProxy, string userAgent)
+    {
+        var webProxy = await GetWebProxy(blProxy);
+        return await TryDownloadString(url, webProxy, userAgent);
+    }
+
+    /// <summary>
+    /// Tries to download string content with a specified proxy.
+    /// </summary>
+    public async Task<string?> TryDownloadString(string url, IWebProxy? webProxy, string userAgent)
     {
         try
         {
-            var result1 = await DownloadStringAsync(url, blProxy, userAgent, 15);
+            var result1 = await DownloadStringAsync(url, webProxy, userAgent, 15);
             if (result1.IsNotEmpty())
             {
                 return result1;
@@ -108,7 +129,7 @@ public class DownloadService
 
         try
         {
-            var result2 = await DownloadStringViaDownloader(url, blProxy, userAgent, 15);
+            var result2 = await DownloadStringViaDownloader(url, webProxy, userAgent, 15);
             if (result2.IsNotEmpty())
             {
                 return result2;
@@ -128,14 +149,12 @@ public class DownloadService
     }
 
     /// <summary>
-    /// DownloadString
+    /// Downloads string content via HttpClient.
     /// </summary>
-    /// <param name="url"></param>
-    private async Task<string?> DownloadStringAsync(string url, bool blProxy, string userAgent, int timeout)
+    private async Task<string?> DownloadStringAsync(string url, IWebProxy? webProxy, string userAgent, int timeout)
     {
         try
         {
-            var webProxy = await GetWebProxy(blProxy);
             var client = new HttpClient(new SocketsHttpHandler()
             {
                 Proxy = webProxy,
@@ -172,15 +191,12 @@ public class DownloadService
     }
 
     /// <summary>
-    /// DownloadString
+    /// Downloads string content via DownloaderHelper.
     /// </summary>
-    /// <param name="url"></param>
-    private async Task<string?> DownloadStringViaDownloader(string url, bool blProxy, string userAgent, int timeout)
+    private async Task<string?> DownloadStringViaDownloader(string url, IWebProxy? webProxy, string userAgent, int timeout)
     {
         try
         {
-            var webProxy = await GetWebProxy(blProxy);
-
             if (userAgent.IsNullOrEmpty())
             {
                 userAgent = Utils.GetVersion(false);
@@ -200,6 +216,9 @@ public class DownloadService
         return null;
     }
 
+    /// <summary>
+    /// Creates local SOCKS proxy when proxy switch is enabled.
+    /// </summary>
     private async Task<WebProxy?> GetWebProxy(bool blProxy)
     {
         if (!blProxy)
@@ -215,6 +234,9 @@ public class DownloadService
         return new WebProxy($"socks5://{Global.Loopback}:{port}");
     }
 
+    /// <summary>
+    /// Checks whether the specified TCP endpoint is reachable.
+    /// </summary>
     private async Task<bool> SocketCheck(string ip, int port)
     {
         try