The problem began when I rebooted the machine that is the ip
helper-address machine. When it came back up none of the machines
could talk to it anymore. It was just that machine.
Rebooting the switch cleared the issue, but I would have preferred
figuring out the problem and correcting it without a reboot.
Do you have any thoughts as to what may have happened and any
suggestions about how to have resolved it without a reboot? Many thanks.