In RH254 Red Hat System Administration III
Section 4.4: Practice: Writing Custom Rules
2.a. Permanently create the new firewall rule
[student@serverX ~]$ sudo firewall-cmd --permanent --add-rich-rule='rule family=ipv4 source address=172.25.X.10/32 service name="http" log level=notice prefix="NEW HTTP " limit value="3/s" accept'
Should it be /24 instead of /32 ?
According to this demonstration, to set rich rule in firewall, this is for a specific host so that's why /32 is used.
If you want to apply the same rule for specific subnet then you can go with /24 or an appropriate CIDR accordingly.