Administering Multicast DNS

The following sections explain how to enable multicast DNS (mDNS) and DNS service discovery. Also provided are examples of how to advertise resources for DNS service discovery.

How to Enable mDNS and DNS Service Discovery

For mDNS and DNS Service Discovery to function, mDNS must be deployed on all systems that are to participate in mDNS. The mDNS service is used to advertise the availability of services provided on the system.

1. Become an administrator.

   For more information, see How to Use Your Assigned Administrative Rights in Oracle Solaris 11.1 Administration: Security Services.

2. If needed, install the mDNS package.

   # pkg install pkg:/service/network/dns/mdns

3. Update name service switch information.

   To be able to resolve local hosts, change the config/host property of the name-service/switch service to include mdns as a source. For example:

   #  /usr/sbin/svccfg -s svc:/system/name-service/switch
   svc:/system/name-service/switch> setprop config/host = astring: "files dns mdns"
   svc:/system/name-service/switch> select system/name-service/switch:default
   svc:/system/name-service/switch:default> refresh
   svc:/system/name-service/switch> quit

4. Enable the mDNS service.

   # svcadm enable svc:/network/dns/multicast:default

   Enabling mDNS in this way ensures that your changes persist through upgrades and reboots. For more information, see the svcadm(1M) man page.

5. (Optional) If needed, check the mDNS error log.

   Check the mDNS service log, /var/svc/log/network-dns-multicast:default.log, for errors or messages.

Advertising Resources for DNS

You can use the dns-sd command as a network diagnosis tool, to browse and discover services, similar to how you would use the ping or traceroute command.

The dns-sd command is primarily for interactive use, mainly because its command-line arguments and its output format can change over time, which makes invoking it from a shell script unpredictable and risky. Additionally, the asynchronous nature of DNS service discovery (DNS-SD) does not easily lend itself to script-oriented programming.

For complete information, see the dns-sd(1M) man page. To incorporate the DNS service in applications, see the libdns-sd(3DNS_SD) man page.

The following are examples of advertising services using DNS service discovery.

Example 3-1 Advertising a Printing Service

The following command advertises the existence of LPR printing service on port 515 on a system called My Test, so that it will be available to DNS-SD compatible printing clients:

# dns-sd -R "My Test" _printer._tcp. . 515 pdl=application/postscript

For this registration to be useful, the LPR service must be available on port 515.

Example 3-2 Advertising a Web Page

The following command advertises a web page being served by an HTTP server on port 80 on the My Test system. The web page will appear on the Bonjour list in Safari and other DNS-SD compatible web clients.

# dns-sd -R "My Test" _http._tcp . 80 path=/path-to-page.html