This chapter intends to explain the basics of how IPP printers let the OS know what attributes it provides. Contrary to how this was done in legacy print, in the IPP world this information is delivered dynamically each time the printer is queried rather than relying on configuration files. Because the printer supplies this information rather than the client relying on a driver, the client can request that information every time the printer is used. If you are just interested in learning some of the concepts without delving too deeply into the implementation of the protocol, this chapter should fit the bill. If you like to tinker around with example code to pursue a more thorough insight into IPP, this chapter can help there as well.