Before installing DirectAdmin, there are some basic programs that you'll need. Check your Operating system and run the following codes:

CentOS 8

yum install iptables wget tar gcc gcc-c++ flex bison make bind bind-libs bind-utils openssl openssl-devel perl quota libaio \
libcom_err-devel libcurl-devel gd zlib-devel zip unzip libcap-devel cronie bzip2 cyrus-sasl-devel perl-ExtUtils-Embed \
autoconf automake libtool which patch mailx bzip2-devel lsof glibc-headers kernel-devel expat-devel \
psmisc net-tools systemd-devel libdb-devel perl-DBI perl-libwww-perl xfsprogs rsyslog logrotate crontabs file \
kernel-headers hostname

Debian 10

apt-get update
apt-get install wget gcc g++ make flex bison openssl libssl-dev perl perl-base perl-modules libperl-dev libperl4-corelibs-perl libwww-perl libaio1 libaio-dev \
zlib1g zlib1g-dev libcap-dev cron bzip2 zip automake autoconf libtool cmake pkg-config python libdb-dev libsasl2-dev \
libncurses5 libncurses5-dev libsystemd-dev bind9 dnsutils quota patch logrotate rsyslog libc6-dev libexpat1-dev \
libcrypt-openssl-rsa-perl libnuma-dev libnuma1