Section 5.2. Advertising Static Services

5.2. Advertising Static Services

If you run your own DNS server, or are friendly with the network administrator who does, then you can create magical results just by adding a few lines to your DNS zone file to create the right records to support the domain-based or address-based Domain Enumeration queries. You just need to add a couple of lines to answer those queries and then add three records for each static service you want to advertise. At Apple, various interesting web pages are statically advertised, so that they magically show up in Safari's Bonjour Bookmarks list. For example, the web page of information for new employees is advertised. You can imagine a scenario that used to happen quite frequently: on a new employee's third day, she would want to find out some information that's available on the New Employees page, but she couldn't remember the URL. She'd ask coworkers around her, but they'd all been at Apple for years and hadn't looked at the New Employees page for a long time, so they couldn't remember the URL either. Thus, a hunt for the New Employees page would begin. That scenario doesn't happen anymore. Now, the page appears in Safari's Bonjour Bookmarks list and any employee, new or old, can find it easily, even if she doesn't remember the URL.

Any organization can easily advertise services this way. A hotel offering network access in its rooms can just add a few lines to their DNS server and have the hotel's web page magically show up in clients' web browser's list of discovered pages. An airport offering 802.11 wireless service can have airport information pages and flight departure times magically appear in passengers' web browsers. A school or university can advertise pages of information relevant to students and visitors. An ISP can advertise pages of information relevant to its customers. A café or coffee shop can advertise pages with menus and price lists.

Example 5-1 shows a very simple example of the lines to add to a DNS zone file to answer Domain Enumeration queries and advertise a single web page in that domain.

Example 5-1. Statically advertising a web page

 ; Invite clients to browse this domain ("@" means "this domain") b._dns-sd._udp                  PTR     @ lb._dns-sd._udp                 PTR     @ ; Advertise our web page ("www.<this domain>" in this example) _http._tcp                      PTR     Our\ Web\ Page._http._tcp Our\ Web\ Page._http._tcp       SRV     0 0 80 www                                 TXT     path=/

For more information on setting up your own DNS server, see DNS and BIND by Paul Albitz and Cricket Liu (O'Reilly).