diff --git a/README.en.md b/README.en.md
index d4f66fe..7788c81 100644
--- a/README.en.md
+++ b/README.en.md
@@ -77,6 +77,9 @@ Configure Minecraft server with the following JVM parameter:
      - Mojang namespace
      - Legacy skin API polyfill
 
+-Dauthlibinjector.httpdPort={port}
+    Sets the port used by the local HTTP server, defaults to 0 (randomly chosen).
+
 -Dauthlibinjector.noShowServerName
     Do not show authentication server name in Minecraft menu screen.
     By default, authlib-injector alters --versionType parameter to display the authentication server name.
diff --git a/README.md b/README.md
index 7c81464..ac4de15 100644
--- a/README.md
+++ b/README.md
@@ -85,6 +85,9 @@ gradle
      - Mojang 命名空间
      - 旧式皮肤 API polyfill
 
+-Dauthlibinjector.httpdPort={端口号}
+    设置内置 HTTP 服务器使用的端口号, 默认为 0 (随机分配).
+
 -Dauthlibinjector.noShowServerName
     不要在 Minecraft 主界面展示验证服务器名称.
     默认情况下, authlib-injector 通过更改 --versionType 参数来在 Minecraft 主界面显示验证服务器名称, 使用本选项可以禁用该功能.
diff --git a/src/main/java/moe/yushi/authlibinjector/Config.java b/src/main/java/moe/yushi/authlibinjector/Config.java
index 2c3f450..bace476 100644
--- a/src/main/java/moe/yushi/authlibinjector/Config.java
+++ b/src/main/java/moe/yushi/authlibinjector/Config.java
@@ -62,6 +62,7 @@ public final class Config {
 	public static FeatureOption mojangAntiFeatures;
 	public static FeatureOption profileKey;
 	public static boolean noShowServerName;
+	public static int httpdPort;
 
 	private static void initDebugOptions() {
 		String prop = System.getProperty("authlibinjector.debug");
@@ -213,5 +214,6 @@ public final class Config {
 		profileKey = parseFeatureOption("authlibinjector.profileKey");
 		httpdDisabled = System.getProperty("authlibinjector.disableHttpd") != null;
 		noShowServerName = System.getProperty("authlibinjector.noShowServerName") != null;
+		httpdPort = Integer.getInteger("authlibinjector.httpdPort", 0);
 	}
 }
diff --git a/src/main/java/moe/yushi/authlibinjector/httpd/URLProcessor.java b/src/main/java/moe/yushi/authlibinjector/httpd/URLProcessor.java
index 7f5441d..cbe0538 100644
--- a/src/main/java/moe/yushi/authlibinjector/httpd/URLProcessor.java
+++ b/src/main/java/moe/yushi/authlibinjector/httpd/URLProcessor.java
@@ -37,6 +37,7 @@ import java.util.Optional;
 import java.util.Set;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
+import moe.yushi.authlibinjector.Config;
 import moe.yushi.authlibinjector.internal.fi.iki.elonen.IHTTPSession;
 import moe.yushi.authlibinjector.internal.fi.iki.elonen.IStatus;
 import moe.yushi.authlibinjector.internal.fi.iki.elonen.NanoHTTPD;
@@ -118,7 +119,7 @@ public class URLProcessor {
 	}
 
 	private NanoHTTPD createHttpd() {
-		return new NanoHTTPD("127.0.0.1", 0) {
+		return new NanoHTTPD("127.0.0.1", Config.httpdPort) {
 			@Override
 			public Response serve(IHTTPSession session) {
 				if (session.getUri().startsWith("/debug/")) {