I wanted to access a RHEL machine from Cacti, so I needed to install and configure net-snmp on there first.
yum install net-snmp
After installing net-snmp the snmpd.conf needs to be configured:
Adding the following enables access from other machines on my local network:
view systemonly included .22.214.171.124.2.1.1 view systemonly included .126.96.36.199.188.8.131.52 rocommunity public 184.108.40.206/32 rocommunity public default -V systemonly rocommunity6 public default -V systemonly
Next I setup the snmpd service to start on boot:
systemctl enable snmpd.service systemctl restart snmpd.service