I am trying to set up CUPS to access a network printer. Its IP address was assigned via DHCP by the internet router, which is also the DHCP server. I understand that this address may change from time to time. How can I instruct CUPS to obtain the printer's IP address?
You have two options here
If you have control over the DHCP server you can set it to assign a static dhcp address (oxymoron I know) to the printer. Most commercial routers I have personally encountered have this feature (see the manual or try to find this in your router configuration)
If you do not have control over address assignments, most printers will either have a hardwired
If you have a more complicated network topology, (say printer is on a different subnet) you will have to configure your network so the hostnames are routable from other subnets.