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TV Model: Panasonic 77LZ2000

tldr: I want to get the name an IP of my panasonic TV using mDNS discovery. I can see other smart devices and my phone (when wireless debugging is switched on) with things like avahi-browse but the TV never appears. Is there a specific setting I need to turn on, to be able to detect this device? Or other testing I can do to figure out why I can't detect it? Or is this even supported on the TV?

Long Version: I'm trying to use mDNS discovery tools to detect my TV on my local network, so I can pull details on it's name and IP address.

I'm running on Linux and was planning to use node mdns to identify all devices on my network and pull the TV info I needed. However the TV didn't appear so I tested some tools (like avahi-browse) to confirm this wasn't just my code and it seems nothing can pick up the TV.

The TV is connected via wireless and is connected to the router itself vs any mesh network and other smart devices that are connected to the router are detectable when I search (like my phone when wireless debugging is on).

I'm assuming there is a setting I have to enable on the TV to make it discoverable like my phone but when searching the TV manual, I didn't find anything on mDNS or how to do this, so it may also not be a feature supported on this TV.

Can someone confirm if this Panasonic does support what I'm trying to do, or additional steps I could try, to get the TV discoverable when I'm checking?

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    How do you know whether the TV supports mDNS at all?
    – grawity_u1686
    Commented May 27 at 9:28
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    I don't, which is why I'm chceking what else I can do to also confirm things like this. I did state it may also not be a feature supported, as I wasn't able to dig anything up when hunting around. So I figued I'd see if anyone can suggest things to also confirm things like this.
    – El_Birdo
    Commented May 27 at 9:33

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Most TVs won't be discoverable via mDNS/DNS-SD, as there are no "standard" media-related services that a TV would offer that way – all of the typical home media stuff instead uses UPnP-based protocols (DLNA), and UPnP primarily uses the SSDP protocol for service discovery. So you would only see DNS-SD advertisements for less common features (AirPlay integration is one thing that comes to mind that uses mDNS/DNS-SD, but at the same time Chromecast integration would use SSDP).

In other words, you need an SSDP discovery tool, e.g. "GUPnP-tools" has gssdp-discover and gupnp-universal-cp (as well as some other related tools for controlling DLNA devices) while the "Gssdp" library has gssdp-device-sniffer. This discovery works over UDP port 1900.

(This is related to, but not quite the same, as the "UPnP" that is used for router port-forwarding – that's done over the UPnP IGD protocol specifically. You can detect your router using a generic SSDP discovery tool, but you won't able to detect your TV using 'upnpc' as it looks specifically for IGD devices.)

The TV might still have a 'bare' mDNS hostname (foo.local), but those exist outside of the DNS-SD discovery mechanism¹, so the only way to see whether a hostname is claimed is by monitoring mDNS traffic using e.g. Wireshark or tcpdump (port 5353).

¹ (Those 'bare' hostnames are merely the building block over which DNS-SD discovery is built.)

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  • Thanks for the detailed explaination. Makes a lot of sense and I've learnt something new :) Confirming I was able to detect the TV with gssdp-discover when turning it off and on. Appriciate the help!
    – El_Birdo
    Commented May 28 at 17:24

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