Today I helped a friend who was having trouble figuring out why their printer was not printing from devices connected to their network.
The issue: Printer only printing when the print job comes from a Windows computer. No other device on the network will print.
What do we know?: We know the printer works because jobs are successful from the Windows computer. That also proves the printer has power and is connected to the same network as the Windows computer.
First check: Are other devices connected to the same network as the printer?
Answer: After verifying IPs on affected devices, with the ipconfig command and via settings app, it was clear that all devices were on the same network.
Next check: Can devices “talk” to each other?
Answer: Using the ping command was able to verify that some devices could reach the printer and vice versa but some could not. Turns out the one that could was able to print.
Next check: What do the devices that can’t be pinged by the printer have in common.
Answer: They are all iOS devices. After some research I learned that iOS devices do not respond to ping requests. I also learned that AirPrint requires mDNS (aka Bonjour) to allow Apple devices to discover network printers.
Next check: Is mDNS setting set on the printer?
Answer: The setting was not on.
Conclusion: After setting mDNS to on the devices were able to send jobs to the printer and print with no problem.
After narrowing the scope to iOS devices I was able to do some research and learn about the Bonjour service and now I know that it is required in order for Apple devices to use a network printer.