I followed this guide: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html-single/installing_identity_management/index#opening-the-ports-required-by-idm_preparing-the-system-for-ipa-server-installation
Configured Chronyd (edited /etc/chrony.conf to use the pfSense as an NTP server)
Checked the status using chronyc tracking.
Updated the firewall, using firewall-cmd --permanent --add-service={freeipa-4,dns} then ran firewall-cmd --reload.
Enabled the required repos:
subscription-manager repos --enable=rhel-9-for-x86_64-baseos-rpms
subscription-manager repos --enable=rhel-9-for-x86_64-appstream-rpms
Then installed the packages for IdM server with integrated DNS:
dnf install ipa-server ipa-server-dns
Then I completed the setup and whatnot…