Re: What is the purpose of mDNS

[Lee <ler762@gmail.com>]

On Sat, Aug 3, 2024 at 6:51 AM George at Clug wrote:
>
> Hi,
>
> What is the purpose of mDNS ?

"zero-configuration networking" seems to be the search term
eg - https://en.wikipedia.org/wiki/Bonjour_(software)

>  It seems to be for multicast?

no, it _uses_ multicast.

<rant> when  did "utilize" replace "use"? </rant>

install wireshark, do a capture with a capture filter of "host
224.0.0.251" and see what's happening on your network.
I see what looks like advertisements for the two printers on my
network and my iPhone constantly querying for

User Datagram Protocol, Src Port: 5353, Dst Port: 5353
Multicast Domain Name System (query)
    Transaction ID: 0x0000
    Flags: 0x0000 Standard query
    Questions: 4
    Answer RRs: 0
    Authority RRs: 0
    Additional RRs: 1
    Queries
        lb._dns-sd._udp.local: type PTR, class IN, "QU" question
        _companion-link._tcp.local: type PTR, class IN, "QU" question
        _homekit._tcp.local: type PTR, class IN, "QU" question
        _sleep-proxy._udp.local: type PTR, class IN, "QU" question


> What other use?

zeroconf printing on Debian?  I just installed Debian on a laptop.  I
haven't done anything wrt printing or printer configuration on this
laptop and yet if I open mousepad and click on File / Print - both
printers show up in the printer list.

Regards,
Lee