diff --git a/install.sh b/install.sh
index c10e6f1..31485d2 100755
--- a/install.sh
+++ b/install.sh
@@ -31,13 +31,13 @@ fi
 apt-get update
 
 # install pwgen, used to create random passwords
-apt -y install pwgen
+DEBIAN_FRONTEND=noninteractive apt-get -y install pwgen
 
 # install mariadb (mysql)
 if [ ! -d "/etc/mysql/" ]; then
 
   MARIADBPWORD=`pwgen 12 1`
-  apt -y install mariadb-client mariadb-server
+  DEBIAN_FRONTEND=noninteractive apt-get -y install mariadb-client mariadb-server
   # set unix_socket auth for root
   mysql -e "GRANT ALL ON *.* TO 'root'@'localhost' IDENTIFIED VIA unix_socket WITH GRANT OPTION"
   # create nagios user for monitoring server status only
@@ -55,10 +55,10 @@ mysql -e "GRANT ALL PRIVILEGES ON vmail.* TO 'vmail'@'localhost';"
 mysqladmin flush-privileges
 
 # install mail server software
-apt -y install exim4-daemon-heavy spf-tools-perl spamassassin srs libclass-dbi-mysql-perl dovecot-core dovecot-imapd dovecot-mysql dovecot-pop3d dovecot-lmtpd
+DEBIAN_FRONTEND=noninteractive apt-get -y install exim4-daemon-heavy spf-tools-perl spamassassin srs libclass-dbi-mysql-perl dovecot-core dovecot-imapd dovecot-mysql dovecot-pop3d dovecot-lmtpd
 
 # configure system users
-apt -y install ssl-cert
+DEBIAN_FRONTEND=noninteractive apt-get -y install ssl-cert
 usermod -a -G ssl-cert Debian-exim
 useradd --create-home --home-dir /var/vmail --shell /usr/sbin/nologin --system --user-group vmail