diff --git a/default/config.yaml b/default/config.yaml
index 04c9a528f..94673ca11 100644
--- a/default/config.yaml
+++ b/default/config.yaml
@@ -7,6 +7,8 @@ cardsCacheCapacity: 100
 # Listen for incoming connections
 listen: false
 # Enables IPv6 and/or IPv4 protocols. Need to have at least one enabled!
+# - Use option "auto" to automatically detect support
+# - Use true or false (no qoutes) to enable or disable each protocol
 protocol:
     ipv4: true
     ipv6: false
diff --git a/server.js b/server.js
index 3fd56bfd3..e62562e56 100644
--- a/server.js
+++ b/server.js
@@ -4,6 +4,7 @@
 import fs from 'node:fs';
 import http from 'node:http';
 import https from 'node:https';
+import os from 'os';
 import path from 'node:path';
 import util from 'node:util';
 import net from 'node:net';
@@ -65,6 +66,9 @@ import {
     forwardFetchResponse,
     removeColorFormatting,
     getSeparator,
+    stringToBool,
+    urlHostnameToIPv6,
+    canResolve,
     safeReadFileSync,
     setupLogLevel,
 } from './src/util.js';
@@ -150,11 +154,11 @@ const DEFAULT_PROXY_BYPASS = [];
 const cliArguments = yargs(hideBin(process.argv))
     .usage('Usage: <your-start-script> <command> [options]')
     .option('enableIPv6', {
-        type: 'boolean',
+        type: 'string',
         default: null,
         describe: `Enables IPv6.\n[config default: ${DEFAULT_ENABLE_IPV6}]`,
     }).option('enableIPv4', {
-        type: 'boolean',
+        type: 'string',
         default: null,
         describe: `Enables IPv4.\n[config default: ${DEFAULT_ENABLE_IPV4}]`,
     }).option('port', {
@@ -243,27 +247,42 @@ app.use(helmet({
 app.use(compression());
 app.use(responseTime());
 
+
+/** @type {number} */
 const server_port = cliArguments.port ?? process.env.SILLY_TAVERN_PORT ?? getConfigValue('port', DEFAULT_PORT);
+/** @type {boolean} */
 const autorun = (cliArguments.autorun ?? getConfigValue('autorun', DEFAULT_AUTORUN)) && !cliArguments.ssl;
+/** @type {boolean} */
 const listen = cliArguments.listen ?? getConfigValue('listen', DEFAULT_LISTEN);
+/** @type {boolean} */
 const enableCorsProxy = cliArguments.corsProxy ?? getConfigValue('enableCorsProxy', DEFAULT_CORS_PROXY);
 const enableWhitelist = cliArguments.whitelist ?? getConfigValue('whitelistMode', DEFAULT_WHITELIST);
+/** @type {string} */
 const dataRoot = cliArguments.dataRoot ?? getConfigValue('dataRoot', './data');
+/** @type {boolean} */
 const disableCsrf = cliArguments.disableCsrf ?? getConfigValue('disableCsrfProtection', DEFAULT_CSRF_DISABLED);
 const basicAuthMode = cliArguments.basicAuthMode ?? getConfigValue('basicAuthMode', DEFAULT_BASIC_AUTH);
 const perUserBasicAuth = getConfigValue('perUserBasicAuth', DEFAULT_PER_USER_BASIC_AUTH);
+/** @type {boolean} */
 const enableAccounts = getConfigValue('enableUserAccounts', DEFAULT_ACCOUNTS);
 
 const uploadsPath = path.join(dataRoot, UPLOADS_DIRECTORY);
 
-const enableIPv6 = cliArguments.enableIPv6 ?? getConfigValue('protocol.ipv6', DEFAULT_ENABLE_IPV6);
-const enableIPv4 = cliArguments.enableIPv4 ?? getConfigValue('protocol.ipv4', DEFAULT_ENABLE_IPV4);
 
+/** @type {boolean | "auto"} */
+let enableIPv6 = stringToBool(cliArguments.enableIPv6) ?? getConfigValue('protocol.ipv6', DEFAULT_ENABLE_IPV6);
+/** @type {boolean | "auto"} */
+let enableIPv4 = stringToBool(cliArguments.enableIPv4) ?? getConfigValue('protocol.ipv4', DEFAULT_ENABLE_IPV4);
+
+/** @type {string} */
 const autorunHostname = cliArguments.autorunHostname ?? getConfigValue('autorunHostname', DEFAULT_AUTORUN_HOSTNAME);
+/** @type {number} */
 const autorunPortOverride = cliArguments.autorunPortOverride ?? getConfigValue('autorunPortOverride', DEFAULT_AUTORUN_PORT);
 
+/** @type {boolean} */
 const dnsPreferIPv6 = cliArguments.dnsPreferIPv6 ?? getConfigValue('dnsPreferIPv6', DEFAULT_PREFER_IPV6);
 
+/** @type {boolean} */
 const avoidLocalhost = cliArguments.avoidLocalhost ?? getConfigValue('avoidLocalhost', DEFAULT_AVOID_LOCALHOST);
 
 const proxyEnabled = cliArguments.requestProxyEnabled ?? getConfigValue('requestProxy.enabled', DEFAULT_PROXY_ENABLED);
@@ -280,7 +299,19 @@ if (dnsPreferIPv6) {
     console.log('Preferring IPv4 for DNS resolution');
 }
 
-if (!enableIPv6 && !enableIPv4) {
+
+const ipOptions = [true, 'auto', false];
+
+if (!ipOptions.includes(enableIPv6)) {
+    console.warn(color.red('`protocol: ipv6` option invalid'), '\n use:', ipOptions, '\n setting to:', DEFAULT_ENABLE_IPV6);
+    enableIPv6 = DEFAULT_ENABLE_IPV6;
+}
+if (!ipOptions.includes(enableIPv4)) {
+    console.warn(color.red('`protocol: ipv4` option invalid'), '\n use:', ipOptions, '\n setting to:', DEFAULT_ENABLE_IPV4);
+    enableIPv4 = DEFAULT_ENABLE_IPV4;
+}
+
+if (enableIPv6 === false && enableIPv4 === false) {
     console.error('error: You can\'t disable all internet protocols: at least IPv6 or IPv4 must be enabled.');
     process.exit(1);
 }
@@ -365,6 +396,55 @@ function getSessionCookieAge() {
     return undefined;
 }
 
+/**
+ * Checks the network interfaces to determine the presence of IPv6 and IPv4 addresses.
+ *
+ * @returns {Promise<[boolean, boolean, boolean, boolean]>} A promise that resolves to an array containing:
+ * - [0]: `hasIPv6` (boolean) - Whether the computer has any IPv6 address, including (`::1`).
+ * - [1]: `hasIPv4` (boolean) - Whether the computer has any IPv4 address, including (`127.0.0.1`).
+ * - [2]: `hasIPv6Local` (boolean) - Whether the computer has local IPv6 address (`::1`).
+ * - [3]: `hasIPv4Local` (boolean) - Whether the computer has local IPv4 address (`127.0.0.1`).
+ */
+async function getHasIP() {
+    let hasIPv6 = false;
+    let hasIPv6Local = false;
+
+    let hasIPv4 = false;
+    let hasIPv4Local = false;
+
+    const interfaces = os.networkInterfaces();
+
+    for (const iface of Object.values(interfaces)) {
+        if (iface === undefined) {
+            continue;
+        }
+
+        for (const info of iface) {
+            if (info.family === 'IPv6') {
+                hasIPv6 = true;
+                if (info.address === '::1') {
+                    hasIPv6Local = true;
+                }
+            }
+
+            if (info.family === 'IPv4') {
+                hasIPv4 = true;
+                if (info.address === '127.0.0.1') {
+                    hasIPv4Local = true;
+                }
+            }
+            if (hasIPv6 && hasIPv4 && hasIPv6Local && hasIPv4Local) break;
+        }
+        if (hasIPv6 && hasIPv4 && hasIPv6Local && hasIPv4Local) break;
+    }
+    return [
+        hasIPv6,
+        hasIPv4,
+        hasIPv6Local,
+        hasIPv4Local,
+    ];
+}
+
 app.use(cookieSession({
     name: getCookieSessionName(),
     sameSite: 'strict',
@@ -694,21 +774,23 @@ const preSetupTasks = async function () {
 
 /**
  * Gets the hostname to use for autorun in the browser.
- * @returns {string} The hostname to use for autorun
+ * @param {boolean} useIPv6 If use IPv6
+ * @param {boolean} useIPv4 If use IPv4
+ * @returns Promise<string> The hostname to use for autorun
  */
-function getAutorunHostname() {
+async function getAutorunHostname(useIPv6, useIPv4) {
     if (autorunHostname === 'auto') {
-        if (enableIPv6 && enableIPv4) {
-            return avoidLocalhost
-                ? '[::1]'
-                : 'localhost';
+        let localhostResolve = await canResolve('localhost', useIPv6, useIPv4);
+
+        if (useIPv6 && useIPv4) {
+            return (avoidLocalhost || !localhostResolve) ? '[::1]' : 'localhost';
         }
 
-        if (enableIPv6) {
+        if (useIPv6) {
             return '[::1]';
         }
 
-        if (enableIPv4) {
+        if (useIPv4) {
             return '127.0.0.1';
         }
     }
@@ -720,11 +802,13 @@ function getAutorunHostname() {
  * Tasks that need to be run after the server starts listening.
  * @param {boolean} v6Failed If the server failed to start on IPv6
  * @param {boolean} v4Failed If the server failed to start on IPv4
+ * @param {boolean} useIPv6 If the server is using IPv6
+ * @param {boolean} useIPv4 If the server is using IPv4
  */
-const postSetupTasks = async function (v6Failed, v4Failed) {
+const postSetupTasks = async function (v6Failed, v4Failed, useIPv6, useIPv4) {
     const autorunUrl = new URL(
         (cliArguments.ssl ? 'https://' : 'http://') +
-        (getAutorunHostname()) +
+        (await getAutorunHostname(useIPv6, useIPv4)) +
         (':') +
         ((autorunPortOverride >= 0) ? autorunPortOverride : server_port),
     );
@@ -737,12 +821,16 @@ const postSetupTasks = async function (v6Failed, v4Failed) {
 
     let logListen = 'SillyTavern is listening on';
 
-    if (enableIPv6 && !v6Failed) {
-        logListen += color.green(' IPv6: ' + tavernUrlV6.host);
+    if (useIPv6 && !v6Failed) {
+        logListen += color.green(
+            ' IPv6: ' + tavernUrlV6.host,
+        );
     }
 
-    if (enableIPv4 && !v4Failed) {
-        logListen += color.green(' IPv4: ' + tavernUrl.host);
+    if (useIPv4 && !v4Failed) {
+        logListen += color.green(
+            ' IPv4: ' + tavernUrl.host,
+        );
     }
 
     const goToLog = 'Go to: ' + color.blue(autorunUrl) + ' to open SillyTavern';
@@ -754,16 +842,22 @@ const postSetupTasks = async function (v6Failed, v4Failed) {
     console.log('\n' + getSeparator(plainGoToLog.length) + '\n');
 
     if (listen) {
-        console.log('[::] or 0.0.0.0 means SillyTavern is listening on all network interfaces (Wi-Fi, LAN, localhost). If you want to limit it only to internal localhost ([::1] or 127.0.0.1), change the setting in config.yaml to "listen: false". Check "access.log" file in the SillyTavern directory if you want to inspect incoming connections.\n');
+        console.log(
+            '[::] or 0.0.0.0 means SillyTavern is listening on all network interfaces (Wi-Fi, LAN, localhost). If you want to limit it only to internal localhost ([::1] or 127.0.0.1), change the setting in config.yaml to "listen: false". Check "access.log" file in the SillyTavern directory if you want to inspect incoming connections.\n',
+        );
     }
 
     if (basicAuthMode) {
         if (perUserBasicAuth && !enableAccounts) {
-            console.error(color.red('Per-user basic authentication is enabled, but user accounts are disabled. This configuration may be insecure.'));
+            console.error(color.red(
+                'Per-user basic authentication is enabled, but user accounts are disabled. This configuration may be insecure.',
+            ));
         } else if (!perUserBasicAuth) {
             const basicAuthUser = getConfigValue('basicAuthUser', {});
             if (!basicAuthUser?.username || !basicAuthUser?.password) {
-                console.warn(color.yellow('Basic Authentication is enabled, but username or password is not set or empty!'));
+                console.warn(color.yellow(
+                    'Basic Authentication is enabled, but username or password is not set or empty!',
+                ));
             }
         }
     }
@@ -818,14 +912,16 @@ function logSecurityAlert(message) {
  * Handles the case where the server failed to start on one or both protocols.
  * @param {boolean} v6Failed If the server failed to start on IPv6
  * @param {boolean} v4Failed If the server failed to start on IPv4
+ * @param {boolean} useIPv6 If use IPv6
+ * @param {boolean} useIPv4 If use IPv4
  */
-function handleServerListenFail(v6Failed, v4Failed) {
-    if (v6Failed && !enableIPv4) {
+function handleServerListenFail(v6Failed, v4Failed, useIPv6, useIPv4) {
+    if (v6Failed && !useIPv4) {
         console.error(color.red('fatal error: Failed to start server on IPv6 and IPv4 disabled'));
         process.exit(1);
     }
 
-    if (v4Failed && !enableIPv6) {
+    if (v4Failed && !useIPv6) {
         console.error(color.red('fatal error: Failed to start server on IPv4 and IPv6 disabled'));
         process.exit(1);
     }
@@ -839,10 +935,11 @@ function handleServerListenFail(v6Failed, v4Failed) {
 /**
  * Creates an HTTPS server.
  * @param {URL} url The URL to listen on
+ * @param {number} ipVersion the ip version to use
  * @returns {Promise<void>} A promise that resolves when the server is listening
  * @throws {Error} If the server fails to start
  */
-function createHttpsServer(url) {
+function createHttpsServer(url, ipVersion) {
     return new Promise((resolve, reject) => {
         const server = https.createServer(
             {
@@ -851,34 +948,56 @@ function createHttpsServer(url) {
             }, app);
         server.on('error', reject);
         server.on('listening', resolve);
-        server.listen(Number(url.port || 443), url.hostname);
+
+        let host = url.hostname;
+        if (ipVersion === 6) host = urlHostnameToIPv6(url.hostname);
+        server.listen({
+            host: host,
+            port: Number(url.port || 443),
+            // see https://nodejs.org/api/net.html#serverlisten for why ipv6Only is used
+            ipv6Only: true,
+        });
     });
 }
 
 /**
  * Creates an HTTP server.
  * @param {URL} url The URL to listen on
+ * @param {number} ipVersion the ip version to use
  * @returns {Promise<void>} A promise that resolves when the server is listening
  * @throws {Error} If the server fails to start
  */
-function createHttpServer(url) {
+function createHttpServer(url, ipVersion) {
     return new Promise((resolve, reject) => {
         const server = http.createServer(app);
         server.on('error', reject);
         server.on('listening', resolve);
-        server.listen(Number(url.port || 80), url.hostname);
+
+        let host = url.hostname;
+        if (ipVersion === 6) host = urlHostnameToIPv6(url.hostname);
+        server.listen({
+            host: host,
+            port: Number(url.port || 80),
+            // see https://nodejs.org/api/net.html#serverlisten for why ipv6Only is used
+            ipv6Only: true,
+        });
     });
 }
 
-async function startHTTPorHTTPS() {
+/**
+ * Starts the server using http or https depending on config
+ * @param {boolean} useIPv6 If use IPv6
+ * @param {boolean} useIPv4 If use IPv4
+ */
+async function startHTTPorHTTPS(useIPv6, useIPv4) {
     let v6Failed = false;
     let v4Failed = false;
 
     const createFunc = cliArguments.ssl ? createHttpsServer : createHttpServer;
 
-    if (enableIPv6) {
+    if (useIPv6) {
         try {
-            await createFunc(tavernUrlV6);
+            await createFunc(tavernUrlV6, 6);
         } catch (error) {
             console.error('non-fatal error: failed to start server on IPv6');
             console.error(error);
@@ -887,9 +1006,9 @@ async function startHTTPorHTTPS() {
         }
     }
 
-    if (enableIPv4) {
+    if (useIPv4) {
         try {
-            await createFunc(tavernUrl);
+            await createFunc(tavernUrl, 4);
         } catch (error) {
             console.error('non-fatal error: failed to start server on IPv4');
             console.error(error);
@@ -902,10 +1021,59 @@ async function startHTTPorHTTPS() {
 }
 
 async function startServer() {
-    const [v6Failed, v4Failed] = await startHTTPorHTTPS();
+    let useIPv6 = (enableIPv6 === true);
+    let useIPv4 = (enableIPv4 === true);
 
-    handleServerListenFail(v6Failed, v4Failed);
-    postSetupTasks(v6Failed, v4Failed);
+    let hasIPv6 = false,
+        hasIPv4 = false,
+        hasIPv6Local = false,
+        hasIPv4Local = false,
+        hasIPv6Any = false,
+        hasIPv4Any = false;
+
+    if (enableIPv6 === 'auto' || enableIPv4 === 'auto') {
+        [hasIPv6Any, hasIPv4Any, hasIPv6Local, hasIPv4Local] = await getHasIP();
+
+        hasIPv6 = listen ? hasIPv6Any : hasIPv6Local;
+        if (enableIPv6 === 'auto') {
+            useIPv6 = hasIPv6;
+        }
+        if (hasIPv6) {
+            if (useIPv6) {
+                console.log(color.green('IPv6 support detected'));
+            } else {
+                console.log('IPv6 support detected (but disabled)');
+            }
+        }
+
+        hasIPv4 = listen ? hasIPv4Any : hasIPv4Local;
+        if (enableIPv4 === 'auto') {
+            useIPv4 = hasIPv4;
+        }
+        if (hasIPv4) {
+            if (useIPv4) {
+                console.log(color.green('IPv4 support detected'));
+            } else {
+                console.log('IPv4 support detected (but disabled)');
+            }
+        }
+
+        if (enableIPv6 === 'auto' && enableIPv4 === 'auto') {
+            if (!hasIPv6 && !hasIPv4) {
+                console.error('Both IPv6 and IPv4 are not detected');
+                process.exit(1);
+            }
+        }
+    }
+
+    if (!useIPv6 && !useIPv4) {
+        console.error('Both IPv6 and IPv4 are disabled,\nP.S. you should never see this error, at least at one point it was checked for before this, with the rest of the config options');
+        process.exit(1);
+    }
+
+    const [v6Failed, v4Failed] = await startHTTPorHTTPS(useIPv6, useIPv4);
+    handleServerListenFail(v6Failed, v4Failed, useIPv6, useIPv4);
+    postSetupTasks(v6Failed, v4Failed, useIPv6, useIPv4);
 }
 
 async function verifySecuritySettings() {
diff --git a/src/util.js b/src/util.js
index 7ca3a5683..426b238ce 100644
--- a/src/util.js
+++ b/src/util.js
@@ -5,6 +5,7 @@ import process from 'node:process';
 import { Readable } from 'node:stream';
 import { createRequire } from 'node:module';
 import { Buffer } from 'node:buffer';
+import { promises as dnsPromise } from 'node:dns';
 
 import yaml from 'yaml';
 import { sync as commandExistsSync } from 'command-exists';
@@ -694,6 +695,70 @@ export function isValidUrl(url) {
     }
 }
 
+/**
+ * removes starting `[` or ending `]` from hostname.
+ * @param {string} hostname hostname to use
+ * @returns {string} hostname plus the modifications
+ */
+export function urlHostnameToIPv6(hostname) {
+    if (hostname.startsWith('[')) {
+        hostname = hostname.slice(1);
+    }
+    if (hostname.endsWith(']')) {
+        hostname = hostname.slice(0, -1);
+    }
+    return hostname;
+}
+
+/**
+ * Test if can resolve a dns name.
+ * @param {string} name Domain name to use
+ * @param {boolean} useIPv6 If use IPv6
+ * @param {boolean} useIPv4 If use IPv4
+ * @returns Promise<boolean> If the URL is valid
+ */
+export async function canResolve(name, useIPv6 = true, useIPv4 = true) {
+    try {
+        let v6Resolved = false;
+        let v4Resolved = false;
+
+        if (useIPv6) {
+            try {
+                await dnsPromise.resolve6(name);
+                v6Resolved = true;
+            } catch (error) {
+                v6Resolved = false;
+            }
+        }
+
+        if (useIPv4) {
+            try {
+                await dnsPromise.resolve(name);
+                v4Resolved = true;
+            } catch (error) {
+                v4Resolved = false;
+            }
+        }
+
+        return v6Resolved || v4Resolved;
+
+    } catch (error) {
+        return false;
+    }
+}
+
+
+/**
+ * converts string to boolean accepts 'true' or 'false' else it returns the string put in
+ * @param {string|null} str Input string or null
+ * @returns {boolean|string|null} boolean else original input string or null if input is
+ */
+export function stringToBool(str) {
+    if (str === 'true') return true;
+    if (str === 'false') return false;
+    return str;
+}
+
 /**
  * Setup the minimum log level
  */