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In this document, we'll cover the easiest way to properly configure your Ubiquiti network for use with mDNS and multicast devices, and get a basic understanding of the changes made.
While the instructions below are specific to current Ubiquiti products, the general concepts should apply to most managed networks.
We'll cover enabling IGMP and mDNS, and then configuring routing to allow mDNS and multicast traffic to flow correctly.
Assumptions and caveats
We're assuming you're using a fully managed network, and specifically for this document, a Ubiquiti network.(Routers, switches and possibly wireless access points)already operational with static IPs assigned to all Ubiquiti hardware.
If any part of the network is NOT manually managed or configured to work in unison with the rest of the network, it will fail due to incompatibilities in how network devices communicate.
Therefore, it is highly recommended to use the same top-down managed network devices to avoid frustrations caused by incompatibilities.
After all changes have been made to make your network fully functional for multicast and mDNS, please note that mDNS routing is not a "permanent" change and will therefore be overwritten by cycling or "mounting" network switches . which means these steps must be performed again.
We are not responsible for any problems or losses that may arise from following the instructions contained in this document and you implement the instructions at your own risk.
Symptoms of a misconfigured network...
- mDNS
- If you use a discovery or configuration tool, it cannot find your device connected to the same network
- If you use a discovery or configuration tool, it randomly finds devices that also randomly disappear
- Multicast
- When connected to a multicast source, your video may appear to "smudge" or "smudge".
- When you connect to a multicast source and have a successful connection but are not receiving any content
- Your network fails when connecting to a multicast source
- When you connect to a multicast source, your network slows down to an unusable speed
Overview of issues and steps
If more than 1 (one) network switch is used in a situation where devices and applications use mDNS for discovery, the switches must be informed which switch will be the “owner” of the mDNS discovery tables.
When the IGMP Snooping Querier is enabled, it periodically sends out queries that trigger IGMP response messages from hosts requesting to receive multicast IP traffic.
These tables are your network references when trying to route traffic to your device. If tables are not properly kept in one place, discovery will be sporadic at best.
The next step is to enable IGMP and possibly, depending on your exact needs, enable or disable multicast traffic over wireless access points.
Multicast traffic on your WiFi network is not a decision to be taken lightly as it is all too easy to overload a wireless access point with multicast traffic. It should also be noted that not all wireless access points are capable of handling multicast traffic; see manufacturer documentation.
Ubiquiti gear used for this documentation
- (1) UC-CK “Unifi Cloud Key” or “Responsible”
- Firmware-Version 5.7.23-10670
- (1) USG „Unified Security Gateway“
- Firmware-Version 4.4.18.5052172
- (1) US-48-750 „48-Port 750W PoE+ Switch Gerenciavel“
- Firmware-Version 3.9.27.8537
- (1) US-24-500 „500 W 24 Port PoE+ Managed Switch“
- Firmware-Version 3.9.27.8537
- (1) US-8-150 „8-Port 150W PoE+ Switch Gerenciavel“
- Firmware-Version 3.9.27.8537
- (1) US-8-60 „60 W 8 Port PoE+ Managed Switch“
- Firmware-Version 3.9.27.8537
- (1) UAP-AC-PRO-US „802.11ac Dual Radio Professional Access Point“
- Firmware-Version 3.9.27.8537
Let's start setting it up!
Enable IGMP snooping
Login to your Ubiquiti network's web interface using "Unifi Web Login" or login directly to your cloud controller/key IP.
After logging in, you will see a "Dashboard" with current network statistics and graphs similar to the ones below.
Click the "Settings" button, which looks like a cog, in the lower-left corner of the "Dashboard" to navigate to the main Network Settings page.
From the left navigation pane, select Networks.
Find your network in the list. If it is a simple network, only one may be listed. Select the EDIT option on the far right of the NAME grid.
Make sure the "Enable IGMP Snooping" checkbox is checked.
Click the "SAVE" button at the bottom of the page.
Wi-Fi IGMPv3 enabled
Now that we've enabled IGMP snooping for the network, let's pick up where we left off and enable the wireless network settings for IGMPv3.
In the navigation pane on the left, select "Wireless & Networks"
You will now get a list of all configured wireless networks. Click the EDIT option on the option you want to use with mDNS and multicast devices.
At the bottom of the wireless page is an option titled "Multicast Enhancement" with a checkbox for "Enable Multicast Enhancement (IGMPv3)", just check that box.
Now click on the “SAVE” button at the bottom of the page.
LAN traffic blocking for WiFi and multicast options
On the same page where we just enabled IGMPv3, we now have some options regarding multicast traffic and how it is handled between the LAN and the wireless network.
By default, the wireless network is configured to allow multicast traffic to pass from the LAN to the wireless network.
This is ok if you are limited to restricted users who are aware of the limitations.
If we want to block multicast traffic from LAN to WiFi, just check the box "Block multicast and streaming data from LAN to WiFi".
You can notice that when it's enabled; By default, the system adds the USG as an exception to the rule.
These exceptions allow you to define specific hardware that is allowed to send multicast traffic from the LAN to the wireless network.
If you are using wireless multicast, this is a highly recommended implementation method.
Add additional hardware that may be attempting to access multicast sources over the wireless network to this exception list.
Note that you don't need to define any additional devices here if you want to access all multicast sources on your LAN.
Click the "SAVE" button below.
Enabling mDNS
Now that we've configured IGMP and multicast filtering, let's pick up where we left off and enable mDNS.
In the navigation pane on the left, select "Services"
Now you will see a top bar with one of the "MDNS" options, select that option.
Click the toggle button to set Enable Multicast DNS to ON
Click "APPLY CHANGES".
Some good news...
You have configured EVERYTHING you can configure with Ubiquiti via the WebUI for multicast traffic and mDNS discovery.
And some bad news...
If you have a network with more than one (1) switch, this configuration is not sufficient.
And another piece of good news...
Using the steps below, we will log into each switch on the network and manually configure the switches to communicate correctly.
So let's get ready!
Configure Logical Poller and Polling Interval for each switch
Before you begin, you must make an important decision...
Which network switch hosts the mDNS records?
The simplest solution is to choose the network switch that results in the fewest "hops" between communicating multicast computers.
Basically, we want to choose the network switch that is most central to all other switches and the multicast devices used on them.
Once you have identified this switch, make note of the assigned static IP address as we will be using this IP address to manually configure each switch on the network.
First, go to the DEVICES page, represented by the circle-in-circle icon on the right.
Highlight the first switch in the list, whatever it is, and the properties window will open. Click on the "Tools" option.
Click the "OPEN TERMINAL" button and a new window will open, connecting to the switch's command line interface "CLI".
Now let's type the following commands, followed by a return when [ENTER] is displayed
host local telnet
[ENTER]
[ENTER]
em
[ENTER]
set up
[ENTER]
Set igmp querier address <Change static IP to host mDNS table>
[ENTER]
set querier igmp querier interval 10
[ENTER]
Salida
[ENTER]
Salida
[ENTER]
These commands are also shown below as an example of my own implementation.
You now need to repeat these EXACT steps using the same static low hop switch IP address for each of the switches on your network (including the low hop switch). Do this on ALL switches in your network or the changes may not successfully resolve your issues.
Also remember that these changes are notNo timestubborn. This means that these logical interrogator and polling interval settings are cleared and must be manually reapplied when your switches are rebooted or when you make any other switch configuration change that causes a deployment.
Applause!
You have now successfully configured your Ubiquiti network to use mDNS and multicast in a multi-switch network deployment!
Please note that we make no endorsement in relation to this document and are not responsible for any impact or loss that may result from following this guide.
Closing remarks:
If any errors or updates are found in this documentation that make this document unnecessary, please let me know and I will be happy to update the documentation accordingly.