diff --git a/backend/server.js b/backend/server.js
index aeb41c4..2ef2fb5 100644
--- a/backend/server.js
+++ b/backend/server.js
@@ -1049,7 +1049,8 @@ app.get('/api/s3/last-modified', async (req, res) => {
             { name: 'asns', key: 'bgp_data/asns.txt' },
             { name: 'servers', key: 'servers.json' },
             { name: 'filters', key: 'filters.json' },
-            { name: 'ipRanges', key: 'bgp_data/ips.txt' }
+            { name: 'ipRanges', key: 'bgp_data/ips.txt' },
+            { name: 'uiSettings', key: 'bgp_data/rt_ui_settings.json' }
         ];
         const results = await Promise.allSettled(
             keys.map(k => s3.headObject({ Bucket: BUCKET_NAME, Key: k.key }).promise())
@@ -1625,6 +1626,70 @@ app.get('/api/auto-urls', async (req, res) => {
     }
 });
 
+// --- UI Settings (rt_ui_settings.json in bgp_data) ---
+// Get UI settings
+app.get('/api/ui-settings', async (req, res) => {
+    const params = {
+        Bucket: BUCKET_NAME,
+        Key: 'bgp_data/rt_ui_settings.json',
+    };
+
+    try {
+        const data = await s3.getObject(params).promise();
+        const jsonText = data.Body.toString('utf-8');
+        let settings = {};
+        try {
+            const parsed = JSON.parse(jsonText);
+            if (parsed && typeof parsed === 'object') settings = parsed;
+        } catch (parseError) {
+            settings = {};
+        }
+        if (data.ETag) res.set('ETag', String(data.ETag));
+        if (data.LastModified) res.set('Last-Modified', new Date(data.LastModified).toUTCString());
+        if (typeof data.ContentLength === 'number') res.set('Content-Length-Source', String(data.ContentLength));
+        return res.json(settings);
+    } catch (error) {
+        if (error.code === 'NoSuchKey') {
+            return res.json({});
+        }
+        console.error('Error reading ui settings from S3:', error);
+        return sendError(res, 500, 'Error reading UI settings from S3', 'E_S3');
+    }
+});
+
+// Update UI settings
+app.post('/api/ui-settings', async (req, res) => {
+    const { settings, etag } = req.body || {};
+    const payload = (settings && typeof settings === 'object') ? settings : {};
+
+    try {
+        // optimistic concurrency if ETag provided (or If-Match header)
+        let current = null;
+        const ifMatch = req.headers['if-match'] ? String(req.headers['if-match']).replace(/\"/g,'"') : null;
+        try { current = await headS3ObjectEtag('bgp_data/rt_ui_settings.json'); } catch {}
+        if (current && (ifMatch || etag) && current !== String(ifMatch || etag)) {
+            const meta = await headMeta('bgp_data/rt_ui_settings.json');
+            return sendError(res, 412, 'Precondition Failed: ETag mismatch', 'E_ETAG_MISMATCH', { currentEtag: current, meta });
+        }
+    } catch {}
+
+    const params = {
+        Bucket: BUCKET_NAME,
+        Key: 'bgp_data/rt_ui_settings.json',
+        Body: JSON.stringify(payload, null, 2),
+        ContentType: 'application/json',
+    };
+
+    try {
+        await s3.putObject(params).promise();
+        const meta = await headMeta('bgp_data/rt_ui_settings.json');
+        return sendOk(res, meta);
+    } catch (error) {
+        console.error('Error writing UI settings to S3:', error);
+        return sendError(res, 500, 'Error writing UI settings to S3', 'E_S3', { error: String(error?.message || error) });
+    }
+});
+
 // --- Servers availability check ---
 // Optimized TCP check: parallelize ports and hosts, cap per-host time, add in-memory TTL cache
 function tcpCheck(host, port, timeoutMs) {
diff --git a/frontend/src/App.jsx b/frontend/src/App.jsx
index aed7b3a..73d9ed0 100644
--- a/frontend/src/App.jsx
+++ b/frontend/src/App.jsx
@@ -22,6 +22,7 @@ import CommunitiesManager from './CommunitiesManager';
 import Dashboard from './Dashboard';
 import './App.css';
 import { NotifyProvider } from './components/NotifyProvider.jsx';
+import SettingsModal from './components/SettingsModal.jsx';
 // axios не используется напрямую; сетевые вызовы через src/lib/api.js
 
 // --- Simple i18n (RU/EN) ---
@@ -96,6 +97,7 @@ function MainLayout() {
   const { lang, setLang, t } = useContext(LanguageContext);
   const { theme, setTheme } = useContext(ThemeContext);
   // Навбар стал лаконичным: без неиспользуемых уведомлений/иконок
+  const [settingsOpen, setSettingsOpen] = useState(false);
 
   // Состояние для управления выпадающими меню
   const [dropdownStates, setDropdownStates] = useState({
@@ -301,6 +303,11 @@ function MainLayout() {
                 <option value="dark">{t('dark')}</option>
               </select>
             </div>
+            <div className="nav-item ms-2">
+              <button className="btn btn-outline-primary btn-sm" onClick={() => setSettingsOpen(true)}>
+                <IconSettings className="me-1" /> Настройки
+              </button>
+            </div>
           </div>
         </div>
       </header>
@@ -318,6 +325,7 @@ function MainLayout() {
           <Route path="/" element={<Navigate to="/dashboard" replace />} />
         </Routes>
       </div>
+      <SettingsModal open={settingsOpen} onClose={() => setSettingsOpen(false)} />
     </div>
   );
 }
diff --git a/frontend/src/components/SettingsModal.jsx b/frontend/src/components/SettingsModal.jsx
new file mode 100644
index 0000000..7bdfc65
--- /dev/null
+++ b/frontend/src/components/SettingsModal.jsx
@@ -0,0 +1,130 @@
+import { useEffect, useRef, useState } from 'react'
+import api from '../lib/api.js'
+
+export default function SettingsModal({ open, onClose }) {
+  const ref = useRef(null)
+  const [loading, setLoading] = useState(false)
+  const [saving, setSaving] = useState(false)
+  const [error, setError] = useState('')
+  const [success, setSuccess] = useState('')
+  const [etag, setEtag] = useState('')
+  const [dohServer, setDohServer] = useState('')
+
+  useEffect(() => {
+    if (!open) return
+    setError('')
+    setSuccess('')
+    setLoading(true)
+    ;(async () => {
+      try {
+        const res = await api.get('/ui-settings')
+        const data = res?.data || {}
+        setDohServer(String(data?.dohServer || ''))
+        const e = res?.headers?.etag || res?.headers?.ETag || ''
+        setEtag(e ? String(e) : '')
+        // фокус на первом поле
+        setTimeout(() => { try { ref.current?.querySelector('input[data-primary]')?.focus() } catch {} }, 0)
+      } catch (e) {
+        setError('Не удалось загрузить настройки')
+      } finally {
+        setLoading(false)
+      }
+    })()
+  }, [open])
+
+  if (!open) return null
+
+  const validateDoh = (value) => {
+    if (!value) return true // допускаем пустое значение
+    try {
+      const u = new URL(String(value))
+      return u.protocol === 'https:'
+    } catch { return false }
+  }
+
+  const onSave = async () => {
+    setError('')
+    setSuccess('')
+    if (!validateDoh(dohServer)) { setError('Укажите корректный HTTPS URL для DoH'); return }
+    setSaving(true)
+    try {
+      const payload = { settings: { dohServer: String(dohServer || '').trim() }, etag }
+      const res = await api.post('/ui-settings', payload)
+      const meta = res?.data || {}
+      setSuccess('Настройки сохранены')
+      setEtag(String(meta?.etag || ''))
+      setTimeout(() => setSuccess(''), 2500)
+    } catch (e) {
+      setError(e?.response?.data?.message || 'Ошибка при сохранении настроек')
+    } finally {
+      setSaving(false)
+    }
+  }
+
+  return (
+    <div className="modal show d-block" role="dialog" aria-modal="true" aria-labelledby="settings-title" style={{ backgroundColor: 'rgba(0,0,0,0.5)' }} onKeyDown={(e) => { if (e.key === 'Escape') onClose?.() }}>
+      <div className="modal-dialog" role="document">
+        <div className="modal-content" ref={ref} tabIndex={-1} onKeyDown={(e) => {
+          if (e.key === 'Tab') {
+            const focusable = ref.current?.querySelectorAll('button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])')
+            if (!focusable || focusable.length === 0) return
+            const first = focusable[0]
+            const last = focusable[focusable.length - 1]
+            if (e.shiftKey && document.activeElement === first) { e.preventDefault(); last.focus(); }
+            else if (!e.shiftKey && document.activeElement === last) { e.preventDefault(); first.focus(); }
+          }
+        }}>
+          <div className="modal-header">
+            <h5 id="settings-title" className="modal-title">Настройки интерфейса</h5>
+            <button type="button" className="btn-close" aria-label="Close" onClick={onClose}></button>
+          </div>
+          <div className="modal-body">
+            {error && (
+              <div className="alert alert-danger alert-dismissible" role="alert">
+                {error}
+                <button type="button" className="btn-close" onClick={() => setError('')}></button>
+              </div>
+            )}
+            {success && (
+              <div className="alert alert-success alert-dismissible" role="alert">
+                {success}
+                <button type="button" className="btn-close" onClick={() => setSuccess('')}></button>
+              </div>
+            )}
+            <div className="mb-3">
+              <label className="form-label">DoH сервер</label>
+              <input
+                type="text"
+                className={`form-control${dohServer && !validateDoh(dohServer) ? ' is-invalid' : ''}`}
+                placeholder="https://dns.google/dns-query"
+                value={dohServer}
+                onChange={(e) => setDohServer(e.target.value)}
+                disabled={loading || saving}
+                data-primary
+              />
+              <div className="form-hint">HTTPS URL для DNS-over-HTTPS (например, https://dns.google/dns-query)</div>
+              {dohServer && !validateDoh(dohServer) && (
+                <div className="invalid-feedback">Укажите корректный HTTPS URL</div>
+              )}
+            </div>
+          </div>
+          <div className="modal-footer">
+            <button type="button" className="btn btn-secondary" onClick={onClose} disabled={saving}>Закрыть</button>
+            <button type="button" className="btn btn-primary" onClick={onSave} disabled={saving || loading}>
+              {saving ? (
+                <>
+                  <span className="spinner-border spinner-border-sm me-2" role="status" />
+                  Сохранение...
+                </>
+              ) : (
+                'Сохранить'
+              )}
+            </button>
+          </div>
+        </div>
+      </div>
+    </div>
+  )
+}
+
+