This is really a crazy one. I have an ISR4451 the I need to upgrade, however I can't get TFTP to work on this device. I've done this many times, should be super simple. I've open TAC case and the engineer can't figure our why this does not work. I can ping both client/server from each other, no ACL or firewalls in the mix. I even gone so far at to attached a laptop to and empty interface on the router, both in the same subnet(192.166.1.1 and 2/24). Tried TFPT/32 and SolarWinds, used both multiple times with a same laptop. Also used both and laptop to backup configuration from 3850 and 2911 just to validate working.
Simple backup of configuration does not work,
"copy running-config tftp"
follow prompts.
Any ideas.
