Error: Invalid prefix for given prefix length
 

Using Ubuntu server, the following commands have been run:

sudo ip addr add 127.0.0.1/24 dev lo
sudo ip addr route 127.0.0.1/24 dev lo

The route command return the following error:

Error: Invalid prefix for given prefix length

I am not sure why.

Any thoughts?

sudo ip route add 127.0.0.0/24 dev lo

...1 would require /32
https://www.linuxquestions.org/quest...th-4175703568/
Try searching "<the err msg>" [site:linuxquestions.org]

P.S. 127 should be /8 And no route (to it) is needed.
ping 127.255.255.254 # should succeed!

FYI: your hand transcription of 2nd cmd is incorrect, because what you wrote would say:
Command "route" is unknown, try "ip address help".
https://www.cyberciti.biz/faq/linux-...-usage-syntax/