RHEL uses yum or dnf (from version 8) as a frontend to the rpm command to install software packages. Use yum instead of rpm to handle package dependencies correctly.

CentOS 7

If the SKOOR software is installed on CentOS 7 systems, the EPEL (for smem, used by the SKOOR Engine Agent) and NUX Desktop (for ffmpeg) need to be added:

yum install centos-release-scl epel-release.noarch nux-dextop-release firewalld chrony

systemctl restart firewalld && systemctl enable firewalld
systemctl restart chronyd && systemctl enable chronyd

AlmaLinux 8

If the SKOOR software is installed on AlmaLinux 8 systems, the EPEL (for smem, used by the SKOOR Engine Agent) and rpmfusion (for ffmpeg) need to be added:

dnf install epel-release.noarch rpmfusion-free-release.noarch firewalld chrony

systemctl restart firewalld && systemctl enable firewalld
systemctl restart chronyd && systemctl enable chronyd

RockyLinux 9

If the SKOOR software is installed on RockyLinux 9 systems, the EPEL (for smem, used by the SKOOR Engine Agent) and rpmfusion (for ffmpeg) need to be added:

dnf install epel-release rpmfusion-free-release firewalld chrony

systemctl start firewalld && systemctl enable firewalld
systemctl restart chronyd && systemctl enable chronyd

Also crb must be enabled (for libmysql):

dnf config-manager --enable crb

Install additional software

Installing the following packages is recommended:

# yum install net-snmp screen nmap-ncat

Install security updates

Apply all currently available security updates:

# yum --security update

Using yumdownloader to download RPM files (optional)

After installing software, yum discards the downloaded RPM files. To use RPM files for e.g. a local yum repository (see section 4.3.9), the yumdownloader command can be installed:

# yum install yum-utils

It allows downloading specific software packages to a predefined directory. The following command will download the two packages tftp and ftp to the webserver directory /srv/eranger/repo:

# yumdownloader --destdir /srv/eranger/repo tftp ftp

Use the --resolve commandline parameter with yumdownloader to download also dependent rpm packages of the given package. 

Useful yum commands

# yum repolist
# yum list installed
# yum clean all