avahi-daemon
TLDR
Start the Avahi mDNS/DNS-SD daemon
SYNOPSIS
avahi-daemon [options]
DESCRIPTION
avahi-daemon implements Apple's Zeroconf architecture (also known as Rendezvous or Bonjour) on Linux and other Unix-like systems. It registers local IP addresses and static services using mDNS (Multicast DNS) and DNS-SD (DNS Service Discovery) protocols.
The daemon provides service discovery functionality, allowing applications and devices on a local network to automatically discover each other without requiring manual configuration or a central DNS server. It publishes services and responds to service discovery queries from other hosts.
At startup, avahi-daemon reads its configuration from /etc/avahi/avahi-daemon.conf and loads XML service definitions from **/etc/avahi/services/\*.service. When enabled, it also processes /etc/resolv.conf** for unicast DNS server information.
The daemon provides two IPC APIs: a simple protocol used by avahi-dnsconfd and nss-mdns, plus a comprehensive D-Bus interface for application integration.
Signal handling: SIGINT and SIGTERM trigger shutdown, SIGHUP reloads DNS server data and service definitions, and SIGUSR1 dumps cached resource records to syslog for debugging.
PARAMETERS
-f, --file=FILE
Specify configuration file (default: /etc/avahi/avahi-daemon.conf)-D, --daemonize
Daemonize after startup; implies --syslog-s, --syslog
Log to syslog instead of STDERR--debug
Increase verbosity to debug level--no-rlimits
Don't enforce resource limits from configuration file--no-drop-root
Don't drop root privileges (not recommended for security)--no-chroot
Disable chroot operation (requires compile-time support)--no-proc-title
Don't change process name during execution-k, --kill
Terminate running daemon by sending SIGTERM-r, --reload
Reread resolv.conf and service definitions by sending SIGHUP-c, --check
Return 0 if daemon is running, non-zero otherwise-h, --help
Display help information-v, --version
Show version information
FILES
/etc/avahi/avahi-daemon.conf
Main configuration file/etc/avahi/hosts
Static hostname mappings for mDNS publishing**/etc/avahi/services/\*.service**
XML service definition files for static service registration
CAVEATS
Requires network multicast support to function properly. IPv4 link-local addresses (169.254.0.0/16) and multicast addresses must be accessible. Some restrictive firewalls may block mDNS traffic on UDP port 5353.
HISTORY
Avahi was developed as a free software implementation of Apple's Bonjour (originally Rendezvous) protocol suite. The project began in 2004 and has become the de facto standard mDNS/DNS-SD implementation on Linux systems, integrated into major distributions.
SEE ALSO
avahi-daemon.conf(5), avahi.hosts(5), avahi.service(5), avahi-browse(1), avahi-publish(1), avahi-dnsconfd(8)
