Several printers do not stay connected to clients--even though everything has static ip addresses--and they are not searchable across networks i.e. they do not appear with Bonjour.
Ideally I would like to setup DNS so that in all of my networks, printers could just be added with Bonjour, and then as well, the settings would continue to work the next day, assuming the IP addresses, etc. did not change.
Apple says very clearly at the top, here to "use DNS to print across networks," but unfortunately does not explain how to do this! I suspect that gesture was aimed at converging Windows users.
All the resources I find online, seem quite old--for example, here is information that was really exciting, and from Apple, all 3 printers are listed here--but in the OSX Server interface, or the latest OSX, there is not even a way to add many of the services people describe.
To be specific; these are all HP Printers, which support Airprint, and the server is running Yosemite with 5.0.1 (the same problem existed on server 4 as well), with the clients either on Yosemite or 10.11.
The firewall settings for layer 2, 3, and 7 are all correct and not interfering with this, as far as I know (have experimented, with it off). Also I have experimented with enabling and disabling IPv6.