diff --git a/apps/api/src/ldap/dto/ldap-config.dto.ts b/apps/api/src/ldap/dto/ldap-config.dto.ts
index 286b44e..a9798a2 100644
--- a/apps/api/src/ldap/dto/ldap-config.dto.ts
+++ b/apps/api/src/ldap/dto/ldap-config.dto.ts
@@ -53,6 +53,25 @@ export class CreateLdapConfigDto {
  */
 export class UpdateLdapConfigDto extends PartialType(CreateLdapConfigDto) {}
 
+/**
+ * DTO for testing a connection with ad-hoc (not-yet-saved) values, so an
+ * admin can validate server/bindDn/bindPassword before persisting a config.
+ * When omitted, the controller falls back to the tenant's saved config.
+ */
+export class TestConnectionDto {
+  @IsUrl({ protocols: ['ldap', 'ldaps'], require_tld: false })
+  @IsOptional()
+  serverUrl?: string;
+
+  @IsString()
+  @IsOptional()
+  bindDn?: string;
+
+  @IsString()
+  @IsOptional()
+  bindPassword?: string;
+}
+
 /**
  * DTO for creating a field mapping entry (D-17).
  */
diff --git a/apps/api/src/ldap/ldap.controller.ts b/apps/api/src/ldap/ldap.controller.ts
index f61e674..cdfde32 100644
--- a/apps/api/src/ldap/ldap.controller.ts
+++ b/apps/api/src/ldap/ldap.controller.ts
@@ -15,6 +15,7 @@ import { Roles } from '../auth/decorators/roles.decorator';
 import {
   CreateFieldMappingDto,
   CreateLdapConfigDto,
+  TestConnectionDto,
   UpdateLdapConfigDto,
 } from './dto/ldap-config.dto';
 import { LdapConfigService } from './ldap-config.service';
@@ -108,27 +109,35 @@ export class LdapController {
   }
 
   /**
-   * POST /ldap/test-connection - Test LDAP connection with current config.
-   * Returns success/failure with error message.
+   * POST /ldap/test-connection - Test an LDAP connection.
+   *
+   * Accepts optional ad-hoc serverUrl/bindDn/bindPassword so an admin can
+   * validate connection details before ever saving a config. Any field left
+   * out (e.g. bindPassword, which the form never re-sends once masked)
+   * falls back to the tenant's saved config. If no config is saved yet and
+   * the body doesn't supply all three fields, there is nothing to test.
    */
   @Post('test-connection')
   @Roles(Role.ADMIN, Role.SUPER_ADMIN)
-  async testConnection(@Req() req: any) {
+  async testConnection(@Req() req: any, @Body() dto: TestConnectionDto) {
     const tenantId = req.tenantId;
     if (!tenantId) {
       throw new BadRequestException('No tenant context');
     }
 
     const config = await this.ldapConfigService.getConfig(tenantId);
-    if (!config) {
-      throw new NotFoundException('No LDAP config found for this tenant');
+
+    const serverUrl = dto.serverUrl || config?.serverUrl;
+    const bindDn = dto.bindDn || config?.bindDn;
+    const bindPassword = dto.bindPassword || config?.bindPassword;
+
+    if (!serverUrl || !bindDn || !bindPassword) {
+      throw new BadRequestException(
+        'serverUrl, bindDn, and bindPassword are required (either provided directly or from a saved config)',
+      );
     }
 
-    return this.ldapService.testConnection({
-      serverUrl: config.serverUrl,
-      bindDn: config.bindDn,
-      bindPassword: config.bindPassword,
-    });
+    return this.ldapService.testConnection({ serverUrl, bindDn, bindPassword });
   }
 
   /**
diff --git a/apps/web/src/app/(portal)/admin/ldap/page.tsx b/apps/web/src/app/(portal)/admin/ldap/page.tsx
index fa611bf..67d3a38 100644
--- a/apps/web/src/app/(portal)/admin/ldap/page.tsx
+++ b/apps/web/src/app/(portal)/admin/ldap/page.tsx
@@ -155,13 +155,26 @@ export default function AdminLdapPage() {
   const handleTestConnection = async () => {
     setTestResult(null);
     try {
+      // Send the currently entered values so a connection can be validated
+      // before ever saving a config. bindPassword is omitted when blank so
+      // the backend falls back to the saved config's password (masked
+      // fields never get re-sent once a config already exists).
+      const body: Record<string, string> = {};
+      if (formData.serverUrl) body.serverUrl = formData.serverUrl;
+      if (formData.bindDn) body.bindDn = formData.bindDn;
+      if (formData.bindPassword) body.bindPassword = formData.bindPassword;
+
       const res = await fetch(`${API_URL}/ldap/test-connection`, {
         method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
         credentials: 'include',
+        body: JSON.stringify(body),
       });
+      const data = await res.json();
       if (res.ok) {
-        const data = await res.json();
         setTestResult(data);
+      } else {
+        setTestResult({ success: false, error: data.message || 'Test failed' });
       }
     } catch {
       setTestResult({ success: false, error: 'Network error' });
@@ -376,15 +389,17 @@ export default function AdminLdapPage() {
             >
               {saving ? tCommon('loading') : t('save')}
             </button>
-            {config && (
-              <button
-                type="button"
-                onClick={handleTestConnection}
-                className="rounded-md border border-border px-4 py-2 text-sm font-medium text-foreground hover:bg-muted transition-colors"
-              >
-                {t('testConnection')}
-              </button>
-            )}
+            <button
+              type="button"
+              onClick={handleTestConnection}
+              disabled={
+                !config &&
+                !(formData.serverUrl && formData.bindDn && formData.bindPassword)
+              }
+              className="rounded-md border border-border px-4 py-2 text-sm font-medium text-foreground hover:bg-muted transition-colors disabled:opacity-50"
+            >
+              {t('testConnection')}
+            </button>
           </div>
 
           {testResult && (