MDNSD.SERVICE(5)

NAME
mdnsd.service - mdnsd service configuration file

SYNOPSIS
/etc/mdns.d/*.service

DESCRIPTION
mdnsd needs at least one .service file to actively announce itself. The systems that mdnsd targets usually have an SSH or HTTP/HTTPS service, which can be located by end-users with mDNS-SD. E.g., mdnsd may be embedded in your printer, an access point, an industrial switch, or other headless network connected device.

Services are defined one per .service file and only two fields are mandatory:

type TYPE
    The TYPE can be any service type from /etc/services, prefixed with an underscore. E.g., 'ipp' is port 631/tcp, which gives the type _ipp._tcp

port PORT
    The port is the UDP or TCP port to announce. This can also be found in the file /etc/services.

There are also a few optional fields supported, see below for examples:

name STRING
    Free form string to describe service. Usually what is presented to end users by discovery agents.

txt STRING
    Text records are free-form strings that are included in service announcements. Useful for announcing meta data about your service. A STRING with no ‘=’ is announced as a value-less boolean key, per RFC 6763.

target HOST
    Host name to announce as the target of the service's SRV record, i.e., the host the service runs on. Defaults to the daemon's own host name, hostname.local, shared by all of its services. Per RFC 6763 the service PTR always points to the service instance, never to this host.

cname HOST
    Announce an alias (CNAME) for the host, e.g., home.local, so the service can also be reached under a short, friendly name. The alias resolves to the same address as the target host.

EXAMPLES
This section has some examples of mDNS service definitions.

  SSH

    # mDNS-SD advertisement of SSH service
    type _ssh._tcp
    port 22

  FTP

    # mDNS-SD advertisement of FTP service
    name Troglobit FTP Server
    type _ftp._tcp
    port 21
    txt server=uftpd
    txt version=2.6

  HTTP

    # mDNS-SD advertisement of HTTP service
    type _http._tcp
    port 80
    txt server=merecat
    txt version=2.31
    cname home.local

  Printer

    # mDNS-SD advertisement of foo._printer._tcp.local.
    type _printer._tcp
    port 515

  IPP

    # mDNS-SD advertisement of foo._ipp._tcp.local.
    type _ipp._tcp
    port 631

FILES
/etc/services
    List of standard service definitions in UNIX

SEE ALSO
mquery(1), mdnsd(8)

AUTHORS
This mDNS-SD implementation was initially developed by Jeremie Miller <jer@jabber.org> in 2003. Much later Joachim Wiberg <troglobit@gmail.com> adopted it for further development and maintenance mdnsd.service at GitHub: https://github.com/troglobit/mdnsd