What are the required ports that need to be open to join MetaDefender Hardened image to the domain?


Version Check:
  • This article applies to all MetaDefender Kiosk Versions deployed using the OPSWAT Hardened image.

Overview

This article outlines the network ports and protocols required for successfully joining our OPSWAT Windows Hardened Kiosk to an Active Directory (AD) domain. Proper connectivity to domain controllers (DCs) over these ports is essential for authentication, directory services, and group policy processing.


Required Ports and Protocols:

Service

Protocol

Port

Purpose

DNS

TCP/UDP

53

Name resolution for domain controllers

Kerberos

TCP/UDP

88

Authentication with AD

RPC Endpoint Mapper

TCP

135

Required to locate RPC services

NetBIOS Name Service

UDP

137

Legacy environments

NetBIOS Datagram

UDP

138

Legacy environments

NetBIOS Session

TCP

139

Legacy support (may still be required)

LDAP

TCP/UDP

389

Directory queries and authentication

SMB/CIFS

TCP

445

File sharing and SYSVOL/NETLOGON access

Kerberos kpasswd

TCP/UDP

464

 

RPC Dynamic Ports

TCP

49152–65535

Used for AD services, group policy, and replication

Optional (depending on config):

Service

Protocol

Port

Purpose

LDAPS

TCP

636

Secure LDAP (if enforced)

Global Catalog

TCP

3268

AD forest-wide searches

Global Catalog SSL

TCP

3269

Secure GC access

NTP (time sync)

UDP

123

Time synchronization (Kerberos dependency)


Important Notes

  • The Hardened Image blocks all inbound connections by default, but the domain join traffic is primarily outbound from the kiosk to the DC, so it should work as long as there's no network firewall blocking those ports between the kiosk and the DC.

  • To access firewall settings on the Hardened Image, you'll need to go through the MMC snap-in (mmc → Add Snap-in → Windows Defender Firewall), since gpedit.msc shortcuts are restricted.

  • Domain-join state is not preserved across Hardened Image upgrades — you'll need to re-join after each image upgrade.


Validation Steps

After opening the required ports, validate connectivity:

Test

Command

Test DNS Resolution

nslookup <YOUR_DOMAIN.LOCAL>

Test Domain Controller Discovery

nltest /dsgetdc:<YOUR_DOMAIN.LOCAL>

Test Port Connectivity (PowerShell)

Test-NetConnection -<COMPUTER_NAME> <DC_NAME> -Port 389


Common Issues

Issue

Cause

Resolution

"Domain not found"

DNS misconfiguration

Point client DNS to domain controller

"Access denied"

Kerberos failure

Verify time sync (NTP)

Join hangs or times out

Firewall blocking RPC

Open port 135 and dynamic RPC range

Group policy not applied

SMB blocked

Ensure port 445 is open

 



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