Difference between revisions of "Avahi"

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[[Category:Networking]]
 
[[Category:Networking]]
 
[[fr:Avahi]]
 
[[fr:Avahi]]
 +
[[ja:Avahi]]
 
From [[Wikipedia:Avahi (software)]]:
 
From [[Wikipedia:Avahi (software)]]:
 
:''"[http://avahi.org/ Avahi] is a free [[Wikipedia:Zero-configuration networking|Zero-configuration networking]] (zeroconf) implementation, including a system for multicast DNS/DNS-SD service discovery. It allows programs to publish and discover services and hosts running on a local network with no specific configuration. For example you can plug into a network and instantly find printers to print to, files to look at and people to talk to. It is licensed under the GNU Lesser General Public License (LGPL)."''
 
:''"[http://avahi.org/ Avahi] is a free [[Wikipedia:Zero-configuration networking|Zero-configuration networking]] (zeroconf) implementation, including a system for multicast DNS/DNS-SD service discovery. It allows programs to publish and discover services and hosts running on a local network with no specific configuration. For example you can plug into a network and instantly find printers to print to, files to look at and people to talk to. It is licensed under the GNU Lesser General Public License (LGPL)."''
  
 
== Installation ==
 
== Installation ==
[[pacman|Install]] {{Pkg|avahi}} and {{Pkg|nss-mdns}}, available in the [[official repositories]].
+
[[Install]] the {{Pkg|avahi}} package.
 
+
{{Note|After installing Avahi you will need to restart the {{ic|dbus}} [[daemon]] before you can start {{ic|avahi-daemon}}.}}
+
  
 
You can manage the Avahi daemon with {{ic|avahi-daemon.service}} [[systemd#Using units|using systemd]].
 
You can manage the Avahi daemon with {{ic|avahi-daemon.service}} [[systemd#Using units|using systemd]].
  
 
== Using Avahi ==
 
== Using Avahi ==
=== Obtaining IPv4LL IP address ===
 
By default, if you are getting IP using DHCP, you are using the {{Pkg|dhcpcd}} package. It can attempt to obtain an IPv4LL address if it failed to get one via DHCP. By default this option is disabled. To enable it, comment noipv4ll string:
 
 
{{hc|/etc/dhcpcd.conf|
 
...
 
#noipv4ll
 
...}}
 
 
Alternatively, run {{ic|avahi-autoipd}}:
 
# avahi-autoipd -D
 
  
 
=== Hostname resolution ===
 
=== Hostname resolution ===
Avahi also allows you to access computers using their hostnames. '''Note:''' you must install {{Pkg|nss-mdns}} for this to work, and have {{ic|avahi-daemon.service}} enabled and running.
+
Avahi provides local hostname resolution using a "''hostname''.local" naming scheme. To enable it, install the {{Pkg|nss-mdns}} package and start {{ic|avahi-daemon.service}}.
  
Suppose you have machines with names ''maple'', ''fig'' and ''oak'', all running Avahi. Avahi can be set up so that you do not have to manage a {{ic|/etc/hosts}} file for each computer. Instead you can simply use {{ic|maple.local}} to access whatever services ''maple'' has. However by default, {{ic|.local}} querying is disabled in Arch Linux. To enable it edit the file {{ic|/etc/nsswitch.conf}} and change the line:
+
Then, edit the file {{ic|/etc/nsswitch.conf}} and change the line:
  hosts: files myhostname dns
+
  hosts: files dns myhostname
 
to:
 
to:
  hosts: files myhostname mdns_minimal [NOTFOUND=return] dns
+
  hosts: files mdns_minimal [NOTFOUND=return] dns myhostname
  
The {{ic|mdns_minimal}} module handles queries for the {{ic|.local}} TLD only. In case you have configured Avahi to use a different TLD, you'll also need to add the full {{ic|mdns}} module at the end. There also are IPv4-only and IPv6-only modules {{ic|mdns[46](_minimal)}}.
+
{{Note|If you experience slowdowns in resolving {{ic|.local}} hosts try to use {{ic|mdns4_minimal}} instead of {{ic|mdns_minimal}}.}}
 +
 
 +
==== Additional info about mdns ====
 +
 
 +
The {{ic|mdns_minimal}} module handles queries for the {{ic|.local}} TLD only. Note the {{ic|<nowiki>[NOTFOUND=return]</nowiki>}}, which specifies that if {{ic|mdns_minimal}} cannot find {{ic|*.local}}, it will not continue to search for it in {{ic|dns}}, {{ic|myhostname}}, etc. In case you have configured Avahi to use a different TLD, you should replace {{ic|1=mdns_minimal [NOTFOUND=return]}} with the full {{ic|mdns}} module. There also are IPv4-only and IPv6-only modules {{ic|mdns[46](_minimal)}}.
 +
 
 +
==== Tools ====
  
 
Avahi includes several utilities which help you discover the services running on a network. For example, run
 
Avahi includes several utilities which help you discover the services running on a network. For example, run
  avahi-browse -alr
+
  $ avahi-browse -alr
 
to discover services in your network.
 
to discover services in your network.
  
The Avahi Zeroconf Browser ({{ic|avahi-discover}}) shows the various services on your network. You can also browse SSH and VNC Servers using {{ic|bssh}} and {{ic|bvnc}} respectively.
+
The Avahi Zeroconf Browser ({{ic|avahi-discover}} – note that it needs avahi's optional dependencies {{Pkg|pygtk}} and {{Pkg|python2-dbus}}) shows the various services on your network. You can also browse SSH and VNC Servers using {{ic|bssh}} and {{ic|bvnc}} respectively.
  
 
There's a good list of software with Avahi support at their website: http://avahi.org/wiki/Avah4users
 
There's a good list of software with Avahi support at their website: http://avahi.org/wiki/Avah4users
{{Note|{{ic|avahi-discover}} needs pygtk and python-dbus to be installed.}}
 
  
 
===File sharing===
 
===File sharing===
  
 
====NFS====
 
====NFS====
If you have an [[NFS]] share set up, you can use Avahi to be able to automount them in Zeroconf-enabled browsers (such as Konqueror on KDE and Finder on OS X). Create a {{ic|.service}} file in {{ic|/etc/avahi/services}} with the following contents:
+
If you have an [[NFS]] share set up, you can use Avahi to be able to automount them in Zeroconf-enabled browsers (such as Konqueror on KDE and Finder on OS X).
 +
 
 +
Create a {{ic|.service}} file in {{ic|/etc/avahi/services}} with the following contents:
 
{{hc|/etc/avahi/services/nfs_Zephyrus_Music.service|<nowiki>
 
{{hc|/etc/avahi/services/nfs_Zephyrus_Music.service|<nowiki>
<?xml version="1.0" standalone='no'?>
+
<?xml version="1.0" standalone='no'?>
<!DOCTYPE service-group SYSTEM "avahi-service.dtd">
+
<!DOCTYPE service-group SYSTEM "avahi-service.dtd">
<service-group>
+
<service-group>
  <name replace-wildcards="yes">NFS Music Share on %h</name>
+
  <name replace-wildcards="yes">NFS Music Share on %h</name>
  <service>
+
  <service>
    <type>_nfs._tcp</type>
+
    <type>_nfs._tcp</type>
    <port>2049</port>
+
    <port>2049</port>
    <txt-record>path=/data/shared/Music</txt-record>
+
    <txt-record>path=/data/shared/Music</txt-record>
  </service>
+
  </service>
</service-group></nowiki>}}
+
</service-group></nowiki>}}
  
 
The port is correct if you have ''insecure'' as an option in your {{ic|/etc/exports}}; otherwise, it needs to be changed (note that ''insecure'' is needed for OS X clients). The path is the path to your export, or a subdirectory of it. For some reason the automount functionality has been removed from Leopard, however [http://www.macosxhints.com/article.php?story=20071116042238744 a script is available]. This was based upon [http://ubuntuforums.org/showthread.php?p=4387032#post4387032 this post].
 
The port is correct if you have ''insecure'' as an option in your {{ic|/etc/exports}}; otherwise, it needs to be changed (note that ''insecure'' is needed for OS X clients). The path is the path to your export, or a subdirectory of it. For some reason the automount functionality has been removed from Leopard, however [http://www.macosxhints.com/article.php?story=20071116042238744 a script is available]. This was based upon [http://ubuntuforums.org/showthread.php?p=4387032#post4387032 this post].
  
 
====Samba====
 
====Samba====
Should work out-of-the-box.
+
With the Avahi daemon running on both the server and client, the file manager on the client should automatically find the server.
 
+
====GShare====
+
You can grab {{aur|gshare}} from the [[Arch User Repository]] and have shared files between the LAN, with no configuration, no hours in samba hacking, no nothing - it just works.
+
  
 
====Vsftpd====
 
====Vsftpd====
Sourced from [http://ubuntuforums.org/showthread.php?t=218630 ubuntuforums.org].
+
You can also auto-discover regular FTP servers, such as vsftpd. Install the {{Pkg|vsftpd}} package and change the settings of vsftpd according to your own personal preferences (see [http://ubuntuforums.org/showthread.php?t=218630 this thread on ubuntuforums.org] or {{ic|man vsftpd.conf}}).
If you would rather use a regular ftp service, install vsftpd and avahi. Change the settings of vsftpd according to what is shown on the ubuntuforums page or according to your own personal preferences (See 'man vsftpd.conf).
+
  
Create a ftp.service file in /etc/avahi/services and paste in that file
+
Create a {{ic|.service}} file in {{ic|/etc/avahi/services}} with the following contents:
<?xml version="1.0" standalone='no'?>
+
{{hc|/etc/avahi/services/ftp.service|<nowiki>
    <!DOCTYPE service-group SYSTEM "avahi-service.dtd">
+
<?xml version="1.0" standalone='no'?>
    <service-group>
+
<!DOCTYPE service-group SYSTEM "avahi-service.dtd">
    <name>FTP file sharing</name>
+
<service-group>
    <service>
+
  <name>FTP file sharing</name>
 +
  <service>
 
     <type>_ftp._tcp</type>
 
     <type>_ftp._tcp</type>
 
     <port>21</port>
 
     <port>21</port>
    </service>
+
  </service>
    </service-group>
+
</service-group>
When you are done, [[systemd#Using units|restart]] the {{ic|avahi-daemon.service}} and {{ic|vsftpd.service}} services.
+
</nowiki>}}
 +
When you are done, [[restart]] the {{ic|avahi-daemon.service}} and {{ic|vsftpd.service}} services.
  
After that you should be able to browse through the ftp server from another computer in your network. The steps shown in this section are created so that the ftp server is 'advertised' by avahi to the local Zeroconf network.
+
The FTP server should now be advertised by Avahi. You should now be able to find the FTP server from a file manager on another computer in your network. You might need to enable [[#Hostname resolution]] on the client.
  
Unless you are using GNOME or KDE, you might not be able to log in to the ftp server directly through your file manager, and so you will have to use a ftp client pointed to the IP address of the server or the hostname of the machine (as shown in [[Avahi#Hostname_resolution|this section]]).
+
===Link-Local (Bonjour/Zeroconf) chat===
  
====Giver====
+
Avahi can be used for bonjour protocol support under linux. Check [[Wikipedia:Comparison of instant messaging clients]] or [[List of applications#Instant messaging]] for a list of clients supporting the bonjour protocol.
[http://code.google.com/p/giver/ Giver] is a mono program that allows simple file-sharing between two desktops when both are running Giver. All you need to do is click and drag the file to the name or picture of the person you wish to send the file to.
+
  
A package is on the {{AUR|giver}}.
+
===Airprint from Mobile Devices===
 +
Avahi along with CUPS also provides the capability to print to just about any printer from airprint compatible mobile devices. In order to enable print capability from your device, simply create an avahi service file for your printer in /etc/avahi/services and restart avahi. An example of a generic services file for an HP-Laserjet printer would be similar to the following with the {{ic|name}}, {{ic|rp}}, {{ic|ty}}, {{ic|adminurl}} and {{ic|note}} fields changed.
  
Note that this depends on gnome-sharp, which has heavy GNOME dependencies.
+
{{hc|/etc/avahi/services/youFileName.service|<nowiki>
 +
<?xml version="1.0" standalone='no'?><!--*-nxml-*-->
 +
<!DOCTYPE service-group SYSTEM "avahi-service.dtd">
 +
<service-group>
 +
  <name>yourPrnterName</name>
 +
  <service>
 +
    <type>_ipp._tcp</type>
 +
    <subtype>_universal._sub._ipp._tcp</subtype>
 +
    <port>631</port>
 +
    <txt-record>txtver=1</txt-record>
 +
    <txt-record>qtotal=1</txt-record>
 +
    <txt-record>rp=printers/yourPrnterName</txt-record>
 +
    <txt-record>ty=yourPrnterName</txt-record>
 +
    <txt-record>adminurl=http://198.168.7.15:631/printers/yourPrnterName</txt-record>
 +
    <txt-record>note=Office Laserjet 4100n</txt-record>
 +
    <txt-record>priority=0</txt-record>
 +
    <txt-record>product=(GPL Ghostscript)</txt-record>
 +
    <txt-record>printer-state=3</txt-record>
 +
    <txt-record>printer-type=0x801046</txt-record>
 +
    <txt-record>Transparent=T</txt-record>
 +
    <txt-record>Binary=T</txt-record>
 +
    <txt-record>Fax=F</txt-record>
 +
    <txt-record>Color=T</txt-record>
 +
    <txt-record>Duplex=T</txt-record>
 +
    <txt-record>Staple=F</txt-record>
 +
    <txt-record>Copies=T</txt-record>
 +
    <txt-record>Collate=F</txt-record>
 +
    <txt-record>Punch=F</txt-record>
 +
    <txt-record>Bind=F</txt-record>
 +
    <txt-record>Sort=F</txt-record>
 +
    <txt-record>Scan=F</txt-record>
 +
    <txt-record>pdl=application/octet-stream,application/pdf,application/postscript,image/jpeg,image/png,image/urf</txt-record>
 +
    <txt-record>URF=W8,SRGB24,CP1,RS600</txt-record>
 +
  </service>
 +
</service-group>
 +
</nowiki>}}
  
===Link-Local (Bonjour/Zeroconf) chat===
+
Alternatively, https://raw.github.com/tjfontaine/airprint-generate/master/airprint-generate.py can be used to generate Avahi service files. It depends on python2 and pycups. The script can be run using:
  
Avahi can be used for bonjour protocol support under linux. Check [[Wikipedia:Comparison of instant messaging clients]] or [[List of Applications#Instant messaging]] for a list of clients supporting the bonjour protocol.
+
# python2 airprint-generate.py -d /etc/avahi/services
  
===Airprint from Mobile Devices===
+
{{Note|If your printer under http://localhost:631/printers is "Not Shared", this python script won't output any file to /etc/avahi/services; in that case, you'll need to "Modify Printer" under one of the CUPS drop-down menus to turn sharing on. If that doesn't work, check out the ArchWiki on [[CUPS printer sharing]].}}
Avahi along with CUPS also provides the capability to print to just about any printer from airprint compatible mobile devices. In order to enable print capability from your device, simply create an avahi service file for your printer in /etc/avahi/services and restart avahi. An example of a generic services file for an HP-Laserjet printer would be similar to the following with the name, rp, ty, adminurl and note fields changed. Save the file as /etc/avahi/services/youFileName.service:
+
  <?xml version="1.0" standalone='no'?><!--*-nxml-*-->
+
  <!DOCTYPE service-group SYSTEM "avahi-service.dtd">
+
  <service-group>
+
    <name>yourPrnterName</name>
+
    <service>
+
      <type>_ipp._tcp</type>
+
      <subtype>_universal._sub._ipp._tcp</subtype>
+
      <port>631</port>
+
      <txt-record>txtver=1</txt-record>
+
      <txt-record>qtotal=1</txt-record>
+
      <txt-record>rp=printers/yourPrnterName</txt-record>
+
      <txt-record>ty=yourPrnterName</txt-record>
+
      <txt-record>adminurl=http://198.168.7.15:631/printers/yourPrnterName</txt-record>
+
      <txt-record>note=Office Laserjet 4100n</txt-record>
+
      <txt-record>priority=0</txt-record>
+
      <txt-record>product=virtual Printer</txt-record>
+
      <txt-record>printer-state=3</txt-record>
+
      <txt-record>printer-type=0x801046</txt-record>
+
      <txt-record>Transparent=T</txt-record>
+
      <txt-record>Binary=T</txt-record>
+
      <txt-record>Fax=F</txt-record>
+
      <txt-record>Color=T</txt-record>
+
      <txt-record>Duplex=T</txt-record>
+
      <txt-record>Staple=F</txt-record>
+
      <txt-record>Copies=T</txt-record>
+
      <txt-record>Collate=F</txt-record>
+
      <txt-record>Punch=F</txt-record>
+
      <txt-record>Bind=F</txt-record>
+
      <txt-record>Sort=F</txt-record>
+
      <txt-record>Scan=F</txt-record>
+
      <txt-record>pdl=application/octet-stream,application/pdf,application/postscript,image/jpeg,image/png,image/urf</txt-record>
+
      <txt-record>URF=W8,SRGB24,CP1,RS600</txt-record>
+
    </service>
+
  </service-group>
+
 
+
Alternatively, https://raw.github.com/tjfontaine/airprint-generate/master/airprint-generate.py can be used to generate Avahi service files. It depends on python2 and pycups. The script can be run using: {{bc|# python2 airprint-generate.py -d /etc/avahi/services}}
+
  
 
=== Firewall ===
 
=== Firewall ===
Line 141: Line 133:
 
   # iptables -A INPUT -p udp -m udp --dport 5353 -j ACCEPT
 
   # iptables -A INPUT -p udp -m udp --dport 5353 -j ACCEPT
  
If you're following the more-than-useful [[Simple Stateful Firewall]] format for your firewall:
+
If you're following the more-than-useful [[Simple stateful firewall]] format for your firewall:
 
   # iptables -A UDP -p udp -m udp --dport 5353 -j ACCEPT
 
   # iptables -A UDP -p udp -m udp --dport 5353 -j ACCEPT
 +
 +
=== Obtaining IPv4LL IP address ===
 +
 +
{{Merge|dhcpcd|should be merged into the main page}}
 +
 +
By default, if you are getting IP using DHCP, you are using the {{Pkg|dhcpcd}} package. It can attempt to obtain an IPv4LL address if it failed to get one via DHCP. By default this option is disabled. To enable it, comment noipv4ll string:
 +
 +
{{hc|/etc/dhcpcd.conf|
 +
...
 +
#noipv4ll
 +
...}}
 +
 +
Alternatively, run {{ic|avahi-autoipd}}:
 +
# avahi-autoipd -D
 +
 +
=== Customizing Avahi ===
 +
==== Adding Services ====
 +
 +
Avahi advertises the services whose {{ic|*.service}} files are found in {{ic|/etc/avahi/services}}. If you want to advertise a service for which there is no {{ic|*.service}} file, it is very easy to create your own.
 +
 +
As an example, let's say you wanted to advertise a quote of the day (QOTD) service operating per [http://tools.ietf.org/html/rfc865 RFC865] on TCP port 17 which you are running on your machine
 +
 +
The first thing to do is to determine the {{ic|<type>}}. {{ic|man avahi.service}} indicates that the
 +
type should be "the DNS-SD service type for this service. e.g. '_http._tcp'". Since the [http://www.dns-sd.org/ServiceTypes.html DNS-SD register was merged into the IANA register in 2010], we look for the service name on the [http://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml IANA register] or in {{ic|/etc/services}} file. The service name shown there is {{ic|qotd}}. Since we're running QOTD on tcp, we now know the service is {{ic|_qotd._tcp}} and the port (per IANA and RFC865) is 17.
 +
 +
Our {{ic|qotd.service}} file is thus:
 +
 +
{{bc|<nowiki>
 +
<?xml version="1.0" standalone='no'?><!--*-nxml-*-->
 +
<!DOCTYPE service-group SYSTEM "avahi-service.dtd">
 +
 +
<!--
 +
  This file is part of avahi.
 +
 +
  avahi is free software; you can redistribute it and/or modify it
 +
  under the terms of the GNU Lesser General Public License as
 +
  published by the Free Software Foundation; either version 2 of the
 +
  License, or (at your option) any later version.
 +
 +
  avahi is distributed in the hope that it will be useful, but
 +
  WITHOUT ANY WARRANTY; without even the implied warranty of
 +
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 +
  General Public License for more details.
 +
 +
  You should have received a copy of the GNU Lesser General Public
 +
  License along with avahi; if not, write to the Free Software
 +
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 +
  02111-1307 USA.
 +
-->
 +
 +
<!-- See avahi.service(5) for more information about this configuration file -->
 +
 +
<service-group>
 +
 +
  <name replace-wildcards="yes">%h</name>
 +
 +
  <service>
 +
    <type>_qotd._tcp</type>
 +
    <port>17</port>
 +
  </service>
 +
 +
</service-group>
 +
</nowiki>}}
 +
 +
For more complicated scenarios, such as advertising services running on a different server, DNS sub-types and so on, consult {{ic|man avahi.service}}.
 +
 +
==== Modifying the service-types database ====
 +
As noted above, avahi comes with tools to browse advertised services. Both {{ic|avahi-browse}} and {{ic|avahi-discover}} use a database file to furnish descriptions of the relevant service. That database contains the names of many, but not all, services.
 +
 +
Sadly, it doesn't contain the QOTD service we just created. Thus {{ic|avahi-browse -a}} would show the following ugly entry
 +
 +
+ wlp2s0 IPv4 MyServer                                        _qotd._tcp local
 +
 +
===== Getting the Sources =====
 +
 +
First, download the files {{ic|build-db.in}} and {{ic|service-types}} files from the {{ic|service-type-database}} subdirectory in the [https://github.com/lathiat/avahi the avahi github mirror] to a build directory.
 +
 +
wget https://raw.githubusercontent.com/lathiat/avahi/master/service-type-database/build-db.in
 +
wget https://raw.githubusercontent.com/lathiat/avahi/master/service-type-database/service-types
 +
 +
===== Modify the Sources =====
 +
 +
Second, create the following script:
 +
 +
#!/bin/bash
 +
sed -e 's,@PYTHON\@,/usr/bin/python2.7,g' \
 +
    -e 's,@DBM\@,gdbm,g' < build-db.in > build-db
 +
chmod +x build-db
 +
 +
This mimics what the Makefile would do if one were building all of avahi. It creates a file named build-db.
 +
 +
$./whatever_you_named_the_script.sh
 +
$ ls
 +
build-db build-db.in service-types whatever_you_named_the_script.sh
 +
 +
Third, make the changes needed to add your new QOTD service to the {{ic|service-types}} file. This file has one entry per line, with the entries in the format {{ic|type:Human Readable Description}}. Note that the human readable description can contain spaces.
 +
 +
In our example, we add the following entry to the end of the file:
 +
 +
_qotd._tcp:Quote of the Day (QOTD) Server
 +
 +
===== Build and Install the New Database =====
 +
 +
Now run the {{ic|build-db}} python script (be sure to use python2 not python3). This will build the {{ic|service-types.db}} file. Check to make sure it's been built and use {{ic|gdbmtools}} to make sure the new database is loadable and contains the new entry:
 +
 +
$/usr/bin/python2.7 build-db
 +
$ls
 +
build-db build-db.in service-types service-types.db whatever_you_named_the_script.sh
 +
$gdbmtool service-types.db
 +
 +
Welcome to the gdbm tool.  Type ? for help.
 +
 +
gdbmtool>fetch _qotd._tcp
 +
Quote of the Day (QOTD) Server
 +
gdbmtool>quit
 +
 +
Now copy the old database to a backup location, move the new database to the live directory and use {{ic|avahi-browse}} database dump command to make sure avahi sees the new entry:
 +
 +
$cp /usr/lib/avahi/service-types.db /backup-directory
 +
$sudo cp /build-directory/service-types.db /usr/lib/avahi/service-types.db
 +
$avahi-browse -b | grep QOTD
 +
Quote of the Day (QOTD) Server
 +
 +
The entry in {{ic|avahi-browse}} should now be:
 +
 +
+ wlp2s0 IPv4 MyServer                                        Quote of the Day (QOTD) Server local
  
 
==See also==
 
==See also==
 
* [http://avahi.org/ Avahi] - Official project website
 
* [http://avahi.org/ Avahi] - Official project website
* [http://en.wikipedia.org/wiki/Avahi_%28software%29 Wikipedia entry]
+
* [[wikipedia:Avahi (software)|Wikipedia entry]]
 
* [http://www.apple.com/support/downloads/bonjourforwindows.html Bonjour for Windows] - Enable Zeroconf on Windows
 
* [http://www.apple.com/support/downloads/bonjourforwindows.html Bonjour for Windows] - Enable Zeroconf on Windows
 
* http://www.zeroconf.org/
 
* http://www.zeroconf.org/

Latest revision as of 23:33, 17 May 2016

From Wikipedia:Avahi (software):

"Avahi is a free Zero-configuration networking (zeroconf) implementation, including a system for multicast DNS/DNS-SD service discovery. It allows programs to publish and discover services and hosts running on a local network with no specific configuration. For example you can plug into a network and instantly find printers to print to, files to look at and people to talk to. It is licensed under the GNU Lesser General Public License (LGPL)."

Installation

Install the avahi package.

You can manage the Avahi daemon with avahi-daemon.service using systemd.

Using Avahi

Hostname resolution

Avahi provides local hostname resolution using a "hostname.local" naming scheme. To enable it, install the nss-mdns package and start avahi-daemon.service.

Then, edit the file /etc/nsswitch.conf and change the line:

hosts: files dns myhostname

to:

hosts: files mdns_minimal [NOTFOUND=return] dns myhostname
Note: If you experience slowdowns in resolving .local hosts try to use mdns4_minimal instead of mdns_minimal.

Additional info about mdns

The mdns_minimal module handles queries for the .local TLD only. Note the [NOTFOUND=return], which specifies that if mdns_minimal cannot find *.local, it will not continue to search for it in dns, myhostname, etc. In case you have configured Avahi to use a different TLD, you should replace mdns_minimal [NOTFOUND=return] with the full mdns module. There also are IPv4-only and IPv6-only modules mdns[46](_minimal).

Tools

Avahi includes several utilities which help you discover the services running on a network. For example, run

$ avahi-browse -alr

to discover services in your network.

The Avahi Zeroconf Browser (avahi-discover – note that it needs avahi's optional dependencies pygtk and python2-dbus) shows the various services on your network. You can also browse SSH and VNC Servers using bssh and bvnc respectively.

There's a good list of software with Avahi support at their website: http://avahi.org/wiki/Avah4users

File sharing

NFS

If you have an NFS share set up, you can use Avahi to be able to automount them in Zeroconf-enabled browsers (such as Konqueror on KDE and Finder on OS X).

Create a .service file in /etc/avahi/services with the following contents:

/etc/avahi/services/nfs_Zephyrus_Music.service
<?xml version="1.0" standalone='no'?>
<!DOCTYPE service-group SYSTEM "avahi-service.dtd">
<service-group>
  <name replace-wildcards="yes">NFS Music Share on %h</name>
  <service>
    <type>_nfs._tcp</type>
    <port>2049</port>
    <txt-record>path=/data/shared/Music</txt-record>
  </service>
</service-group>

The port is correct if you have insecure as an option in your /etc/exports; otherwise, it needs to be changed (note that insecure is needed for OS X clients). The path is the path to your export, or a subdirectory of it. For some reason the automount functionality has been removed from Leopard, however a script is available. This was based upon this post.

Samba

With the Avahi daemon running on both the server and client, the file manager on the client should automatically find the server.

Vsftpd

You can also auto-discover regular FTP servers, such as vsftpd. Install the vsftpd package and change the settings of vsftpd according to your own personal preferences (see this thread on ubuntuforums.org or man vsftpd.conf).

Create a .service file in /etc/avahi/services with the following contents:

/etc/avahi/services/ftp.service
<?xml version="1.0" standalone='no'?>
<!DOCTYPE service-group SYSTEM "avahi-service.dtd">
<service-group>
  <name>FTP file sharing</name>
  <service>
    <type>_ftp._tcp</type>
    <port>21</port>
  </service>
</service-group>

When you are done, restart the avahi-daemon.service and vsftpd.service services.

The FTP server should now be advertised by Avahi. You should now be able to find the FTP server from a file manager on another computer in your network. You might need to enable #Hostname resolution on the client.

Link-Local (Bonjour/Zeroconf) chat

Avahi can be used for bonjour protocol support under linux. Check Wikipedia:Comparison of instant messaging clients or List of applications#Instant messaging for a list of clients supporting the bonjour protocol.

Airprint from Mobile Devices

Avahi along with CUPS also provides the capability to print to just about any printer from airprint compatible mobile devices. In order to enable print capability from your device, simply create an avahi service file for your printer in /etc/avahi/services and restart avahi. An example of a generic services file for an HP-Laserjet printer would be similar to the following with the name, rp, ty, adminurl and note fields changed.

/etc/avahi/services/youFileName.service
<?xml version="1.0" standalone='no'?><!--*-nxml-*-->
<!DOCTYPE service-group SYSTEM "avahi-service.dtd">
<service-group>
  <name>yourPrnterName</name>
  <service>
    <type>_ipp._tcp</type>
    <subtype>_universal._sub._ipp._tcp</subtype>
    <port>631</port>
    <txt-record>txtver=1</txt-record>
    <txt-record>qtotal=1</txt-record>
    <txt-record>rp=printers/yourPrnterName</txt-record>
    <txt-record>ty=yourPrnterName</txt-record>
    <txt-record>adminurl=http://198.168.7.15:631/printers/yourPrnterName</txt-record>
    <txt-record>note=Office Laserjet 4100n</txt-record>
    <txt-record>priority=0</txt-record>
    <txt-record>product=(GPL Ghostscript)</txt-record>
    <txt-record>printer-state=3</txt-record>
    <txt-record>printer-type=0x801046</txt-record>
    <txt-record>Transparent=T</txt-record>
    <txt-record>Binary=T</txt-record>
    <txt-record>Fax=F</txt-record>
    <txt-record>Color=T</txt-record>
    <txt-record>Duplex=T</txt-record>
    <txt-record>Staple=F</txt-record>
    <txt-record>Copies=T</txt-record>
    <txt-record>Collate=F</txt-record>
    <txt-record>Punch=F</txt-record>
    <txt-record>Bind=F</txt-record>
    <txt-record>Sort=F</txt-record>
    <txt-record>Scan=F</txt-record>
    <txt-record>pdl=application/octet-stream,application/pdf,application/postscript,image/jpeg,image/png,image/urf</txt-record>
    <txt-record>URF=W8,SRGB24,CP1,RS600</txt-record>
  </service>
</service-group>

Alternatively, https://raw.github.com/tjfontaine/airprint-generate/master/airprint-generate.py can be used to generate Avahi service files. It depends on python2 and pycups. The script can be run using:

# python2 airprint-generate.py -d /etc/avahi/services
Note: If your printer under http://localhost:631/printers is "Not Shared", this python script won't output any file to /etc/avahi/services; in that case, you'll need to "Modify Printer" under one of the CUPS drop-down menus to turn sharing on. If that doesn't work, check out the ArchWiki on CUPS printer sharing.

Firewall

Be sure to open UDP port 5353 if you're using iptables:

 # iptables -A INPUT -p udp -m udp --dport 5353 -j ACCEPT

If you're following the more-than-useful Simple stateful firewall format for your firewall:

 # iptables -A UDP -p udp -m udp --dport 5353 -j ACCEPT

Obtaining IPv4LL IP address

Merge-arrows-2.pngThis article or section is a candidate for merging with dhcpcd.Merge-arrows-2.png

Notes: should be merged into the main page (Discuss in Talk:Avahi#)

By default, if you are getting IP using DHCP, you are using the dhcpcd package. It can attempt to obtain an IPv4LL address if it failed to get one via DHCP. By default this option is disabled. To enable it, comment noipv4ll string:

/etc/dhcpcd.conf
...
#noipv4ll
...

Alternatively, run avahi-autoipd:

# avahi-autoipd -D

Customizing Avahi

Adding Services

Avahi advertises the services whose *.service files are found in /etc/avahi/services. If you want to advertise a service for which there is no *.service file, it is very easy to create your own.

As an example, let's say you wanted to advertise a quote of the day (QOTD) service operating per RFC865 on TCP port 17 which you are running on your machine

The first thing to do is to determine the <type>. man avahi.service indicates that the type should be "the DNS-SD service type for this service. e.g. '_http._tcp'". Since the DNS-SD register was merged into the IANA register in 2010, we look for the service name on the IANA register or in /etc/services file. The service name shown there is qotd. Since we're running QOTD on tcp, we now know the service is _qotd._tcp and the port (per IANA and RFC865) is 17.

Our qotd.service file is thus:

<?xml version="1.0" standalone='no'?><!--*-nxml-*-->
<!DOCTYPE service-group SYSTEM "avahi-service.dtd">

<!--
  This file is part of avahi.

  avahi is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as
  published by the Free Software Foundation; either version 2 of the
  License, or (at your option) any later version.

  avahi is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with avahi; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  02111-1307 USA.
-->

<!-- See avahi.service(5) for more information about this configuration file -->

<service-group>

  <name replace-wildcards="yes">%h</name>

  <service>
    <type>_qotd._tcp</type>
    <port>17</port>
  </service>

</service-group>

For more complicated scenarios, such as advertising services running on a different server, DNS sub-types and so on, consult man avahi.service.

Modifying the service-types database

As noted above, avahi comes with tools to browse advertised services. Both avahi-browse and avahi-discover use a database file to furnish descriptions of the relevant service. That database contains the names of many, but not all, services.

Sadly, it doesn't contain the QOTD service we just created. Thus avahi-browse -a would show the following ugly entry

+ wlp2s0 IPv4 MyServer                                        _qotd._tcp local
Getting the Sources

First, download the files build-db.in and service-types files from the service-type-database subdirectory in the the avahi github mirror to a build directory.

wget https://raw.githubusercontent.com/lathiat/avahi/master/service-type-database/build-db.in
wget https://raw.githubusercontent.com/lathiat/avahi/master/service-type-database/service-types
Modify the Sources

Second, create the following script:

#!/bin/bash
sed -e 's,@PYTHON\@,/usr/bin/python2.7,g' \
    -e 's,@DBM\@,gdbm,g' < build-db.in > build-db
chmod +x build-db

This mimics what the Makefile would do if one were building all of avahi. It creates a file named build-db.

$./whatever_you_named_the_script.sh
$ ls
build-db build-db.in service-types whatever_you_named_the_script.sh

Third, make the changes needed to add your new QOTD service to the service-types file. This file has one entry per line, with the entries in the format type:Human Readable Description. Note that the human readable description can contain spaces.

In our example, we add the following entry to the end of the file:

_qotd._tcp:Quote of the Day (QOTD) Server
Build and Install the New Database

Now run the build-db python script (be sure to use python2 not python3). This will build the service-types.db file. Check to make sure it's been built and use gdbmtools to make sure the new database is loadable and contains the new entry:

$/usr/bin/python2.7 build-db
$ls
build-db build-db.in service-types service-types.db whatever_you_named_the_script.sh
$gdbmtool service-types.db

Welcome to the gdbm tool.  Type ? for help.

gdbmtool>fetch _qotd._tcp
Quote of the Day (QOTD) Server
gdbmtool>quit

Now copy the old database to a backup location, move the new database to the live directory and use avahi-browse database dump command to make sure avahi sees the new entry:

$cp /usr/lib/avahi/service-types.db /backup-directory
$sudo cp /build-directory/service-types.db /usr/lib/avahi/service-types.db
$avahi-browse -b | grep QOTD
Quote of the Day (QOTD) Server

The entry in avahi-browse should now be:

+ wlp2s0 IPv4 MyServer                                        Quote of the Day (QOTD) Server local

See also