Mdns port firewall 168. Apr 4, 2022 · To completely lock down mDNS, disable the inbound “mDNS (UDP-In)” rules in Windows Defender Firewall for all profiles (Public, Private, and Domain). I do use the Feb 12, 2014 · If you plan to use LLMNR and use a firewall, make sure to open UDP and TCP ports 5355. on both interfaces to port 5353 at 224. There is an existing rule for this in the predefined firewall rules (which are enabled by default) named Allow incoming multicast DNS requests from the Trusted zone on UDP 5355. set firewall group port-group mDNS port 5353 set firewall name STREAM_LOCAL rule 60 description mDNS Nov 18, 2024 · Port 5353 is associated with the Multicast Domain Name System (mDNS) protocol, which lets devices broadcast their IP addresses to each other within small networks. Below is a detailed explanation of the situation: I. Here’s what to do: Check mDNS Settings: Double-check that mDNS is enabled on the correct network. Security Assessment Non-Malicious Behavior Characteristics The only difference is: Create a new firewall group with type "Address IPv6" and address ff02::fb Create a new firewall rule under Network > Routing & Firewall > Firewall > Rules IPv6 > GUEST LOCAL with IPv6 protocol UDP and destination IPv6 Address Group with the new firewall group's name and destination port set to mDNS Port Jun 11, 2025 · Legacy protocols like Multicast DNS, NetBIOS, and LLMNR create hidden entry points for attackers. Out of the documentation it is not clear to me what firewall rules I need to allow the mDNS multicast traffic between these two vpn. When I checked the firewall logs it was also blocking port 53 also. Oct 13, 2024 · Hello, I want to use the mDNS repeater on OPNsense to forward mDNS between two subnets. Both queries and advertisements/responses are normally multicast to (and I am trying to block mDNS traffic by blocking port 5353. , printer casting, Bonjour services, etc. 8 to reach the python process. JonBuhagiar The caveat with that idea is that mDNS is more peer-to-peer than client-server. Maybe that's the newport if microsoft keep 5353 to mdns? But i'm trying to get rid of it all. Reboot Devices: Sometimes, devices just need a quick reboot to start broadcasting their mDNS information. Adjust the rules if necessary. stackexchange. Remember your machine's firewall will also need to allow the udp packet from 192. I'm seeing port 5353, as you can see from the command on my 1st post. Open Windows Firewall with hit the keys Windows + R and insert firewall. Slow Device Discovery Jun 7, 2025 · The UDP port 5353 you inquired about is primarily used by the system or applications for mDNS (Multicast DNS) services, commonly employed for local network device discovery (e. When doing so, I lost all connectivity to my domain controller and every other network machine. 0. Why would it start blocking DNS? Aug 3, 2024 · Multicast DNS (mDNS) to resolve hostnames IP addresses small networks a dedicated DNS server It is particularly useful in local area networks (LANs) , such as home or office networks , where devices need to discover and communicate with each other dynamically. This should be noted in the HomeKit Device documentation as a prerequisite. See full list on unix. This is useful when users still want to allow mDNS at a global level but only want to block mDNS for some specific subnet/user profile when it generates lots of traffic. Note that ‘STREAM_LOCAL’ is the firewall ruleset applied to the ‘local’ section of the inbound IoT VLAN interface. Ensure you allow udp from the responder to your requester on any port. Apr 11, 2025 · TLDR: For HomeKit Device discovery, open your firewall for mDNS service (UDP port 5353). com May 6, 2023 · I would like to prevent multicast DNS on port 5335. This specific rule cannot be disabled, unfortunately. com Skype: flyingbee. Jun 20, 2023 · HA Firewall Aside from those router rules, the HA host firewall on your HA instance or Host/HA network must allow that local mDNS/Matter traffic in addition to its own limited subset of unprivileged ports like 8123 TPC (the HA portal). g. Check Firewall Rules: Ensure your firewall isn’t blocking mDNS traffic. mDNS by using multicast packets over UDP (User Datagram Protocol) DNS queries all devices on the local network appropriate IP addresses Sep 27, 2024 · This article describes how to block mDNS traffic with firewall policies for a specific subnet or SSID user profile. It worked fine until I blocked UDP port 5353. Apr 29, 2022 · The Windows Firewall contains the predefined rule “mDNS (UDP-In)”. Discover how it impacts networking and best practices for safety. Learn how our cybersecurity team identifies and remediates these vulnerabilities before threat actors can exploit them. Wild. cpl to run it, then go to Advanced Settings . I have port 53 open. Not sure why it was doing that. software Telephone: Support How to open TCP ports 5354, UDP port 5353, and TCP port 631 in the firewall on a Windows PC for Bonjour (mDNS), AirPlay or AirPrint Mar 17, 2022 · EdgeRouter Config Below are the config lines that I used to enable the mDNS repeater function on the EdgeRouter. Check port 5355 . Last edited by gcb (2024-04-02 00:20:24) Offline Jun 2, 2025 · Learn about port 5353: its uses, security risks, and management tips. Not expose even more. . ). 251 and [ff02::fb] or on both interfaces to port 5353 at "subnet address" or on both interfaces to port 5353 at "this firewall" Or a Dec 9, 2024 · Email: support@flyingbee. 50. This will prevent all inbound mDNS traffic from being processed and effectively disable mDNS. Apr 4, 2022 · If mDNS is still required between clients and servers, perhaps a Connection Security Rule in the Windows Defender Firewall with Advanced Security MMC could be created to only allow authenticated computer to respond to UDP 5353. Dec 23, 2022 · If the packets show up in udpbroadcastrelay but the responses aren't reaching your machine, the problem is again likely the firewall. fzyze roypd trklpg uyk ntdv ndhgwyl jub oswm qhrs pmavr jugabk ahiae qjh eabpeiq rkwm