Fail2ban - how to add a range of IP addresses to ignoreip?

Question

linux

Tell me, how to correctly add the address range 81.277.41.100-81.277.41.200 to ignoreip in fail2ban?
Now the line looks like this:
# "ignoreip" can be an IP address, a CIDR mask or a DNS host
ignoreip = 127.0.0.1/8 88.91.34.22/8

Answer 1

First - the address is wrong because of the second octet.
Secondly, you simply cut the desired range into several networks. If not critical, then / 24 can be killed.
81.27.41.96/27 - .96-.127
81.27.41.128/26 - .128-.191
81.27.41.192/28 - .192-.207
You can get confused and cut even smaller so that the excess is not captured.