diff --git a/README.md b/README.md
index f4a0711..cf0558a 100644
--- a/README.md
+++ b/README.md
@@ -32,7 +32,7 @@ By default, the image will use a local SQLite database for storing user account
 It'll be created inside the `/var/www/html` directory and can be backed up from there. Please note that
 this option should not be used for production environments.
 
-### Connect to a MySQL Database
+### Connect to a Database
 
 The recommended way to run Roundcube is connected to a MySQL database. Specify the following env variables to do so:
 
@@ -40,6 +40,8 @@ The recommended way to run Roundcube is connected to a MySQL database. Specify t
 
 `ROUNDCUBEMAIL_DB_HOST` - Host (or Docker instance) name of the database service; defaults to `mysql` or `postgres` depending on linked containers.
 
+`ROUNDCUBEMAIL_DB_PORT` - Port number of the database service; defaults to `3306` or `5432` depending on linked containers.
+
 `ROUNDCUBEMAIL_DB_USER` - The database username for Roundcube; defaults to `root` on `mysql`
 
 `ROUNDCUBEMAIL_DB_PASSWORD` - The password for the database connection
diff --git a/php-apache/docker-entrypoint.sh b/php-apache/docker-entrypoint.sh
index 35fd40b..4262293 100755
--- a/php-apache/docker-entrypoint.sh
+++ b/php-apache/docker-entrypoint.sh
@@ -17,15 +17,17 @@ if [[ "$1" == apache2* ]] || [ "$1" == php-fpm ]; then
   if [ ! -z "${!POSTGRES_ENV_POSTGRES_*}" ] || [ "$ROUNDCUBEMAIL_DB_TYPE" == "pgsql" ]; then
     : "${ROUNDCUBEMAIL_DB_TYPE:=pgsql}"
     : "${ROUNDCUBEMAIL_DB_HOST:=postgres}"
+    : "${ROUNDCUBEMAIL_DB_PORT:=5432}"
     : "${ROUNDCUBEMAIL_DB_USER:=${POSTGRES_ENV_POSTGRES_USER}}"
     : "${ROUNDCUBEMAIL_DB_PASSWORD:=${POSTGRES_ENV_POSTGRES_PASSWORD}}"
     : "${ROUNDCUBEMAIL_DB_NAME:=${POSTGRES_ENV_POSTGRES_DB:-roundcubemail}}"
     : "${ROUNDCUBEMAIL_DSNW:=${ROUNDCUBEMAIL_DB_TYPE}://${ROUNDCUBEMAIL_DB_USER}:${ROUNDCUBEMAIL_DB_PASSWORD}@${ROUNDCUBEMAIL_DB_HOST}/${ROUNDCUBEMAIL_DB_NAME}}"
 
-    /wait-for-it.sh ${ROUNDCUBEMAIL_DB_HOST}:5432 -t 30
+    /wait-for-it.sh ${ROUNDCUBEMAIL_DB_HOST}:${ROUNDCUBEMAIL_DB_PORT} -t 30
   elif [ ! -z "${!MYSQL_ENV_MYSQL_*}" ] || [ "$ROUNDCUBEMAIL_DB_TYPE" == "mysql" ]; then
     : "${ROUNDCUBEMAIL_DB_TYPE:=mysql}"
     : "${ROUNDCUBEMAIL_DB_HOST:=mysql}"
+    : "${ROUNDCUBEMAIL_DB_PORT:=3306}"
     : "${ROUNDCUBEMAIL_DB_USER:=${MYSQL_ENV_MYSQL_USER:-root}}"
     if [ "$ROUNDCUBEMAIL_DB_USER" = 'root' ]; then
       : "${ROUNDCUBEMAIL_DB_PASSWORD:=${MYSQL_ENV_MYSQL_ROOT_PASSWORD}}"
@@ -35,7 +37,7 @@ if [[ "$1" == apache2* ]] || [ "$1" == php-fpm ]; then
     : "${ROUNDCUBEMAIL_DB_NAME:=${MYSQL_ENV_MYSQL_DATABASE:-roundcubemail}}"
     : "${ROUNDCUBEMAIL_DSNW:=${ROUNDCUBEMAIL_DB_TYPE}://${ROUNDCUBEMAIL_DB_USER}:${ROUNDCUBEMAIL_DB_PASSWORD}@${ROUNDCUBEMAIL_DB_HOST}/${ROUNDCUBEMAIL_DB_NAME}}"
 
-    /wait-for-it.sh ${ROUNDCUBEMAIL_DB_HOST}:3306 -t 30
+    /wait-for-it.sh ${ROUNDCUBEMAIL_DB_HOST}:${ROUNDCUBEMAIL_DB_PORT} -t 30
   else
     # use local SQLite DB in /var/www/html/db
     : "${ROUNDCUBEMAIL_DB_TYPE:=sqlite}"
diff --git a/php-fpm/docker-entrypoint.sh b/php-fpm/docker-entrypoint.sh
index 5bc6378..8ff7788 100755
--- a/php-fpm/docker-entrypoint.sh
+++ b/php-fpm/docker-entrypoint.sh
@@ -17,15 +17,17 @@ if [[ "$1" == apache2* ]] || [ "$1" == php-fpm ]; then
   if [ ! -z "${!POSTGRES_ENV_POSTGRES_*}" ] || [ "$ROUNDCUBEMAIL_DB_TYPE" == "pgsql" ]; then
     : "${ROUNDCUBEMAIL_DB_TYPE:=pgsql}"
     : "${ROUNDCUBEMAIL_DB_HOST:=postgres}"
+    : "${ROUNDCUBEMAIL_DB_PORT:=5432}"
     : "${ROUNDCUBEMAIL_DB_USER:=${POSTGRES_ENV_POSTGRES_USER}}"
     : "${ROUNDCUBEMAIL_DB_PASSWORD:=${POSTGRES_ENV_POSTGRES_PASSWORD}}"
     : "${ROUNDCUBEMAIL_DB_NAME:=${POSTGRES_ENV_POSTGRES_DB:-roundcubemail}}"
     : "${ROUNDCUBEMAIL_DSNW:=${ROUNDCUBEMAIL_DB_TYPE}://${ROUNDCUBEMAIL_DB_USER}:${ROUNDCUBEMAIL_DB_PASSWORD}@${ROUNDCUBEMAIL_DB_HOST}/${ROUNDCUBEMAIL_DB_NAME}}"
 
-    /wait-for-it.sh ${ROUNDCUBEMAIL_DB_HOST}:5432 -t 30
+    /wait-for-it.sh ${ROUNDCUBEMAIL_DB_HOST}:${ROUNDCUBEMAIL_DB_PORT} -t 30
   elif [ ! -z "${!MYSQL_ENV_MYSQL_*}" ] || [ "$ROUNDCUBEMAIL_DB_TYPE" == "mysql" ]; then
     : "${ROUNDCUBEMAIL_DB_TYPE:=mysql}"
     : "${ROUNDCUBEMAIL_DB_HOST:=mysql}"
+    : "${ROUNDCUBEMAIL_DB_PORT:=3306}"
     : "${ROUNDCUBEMAIL_DB_USER:=${MYSQL_ENV_MYSQL_USER:-root}}"
     if [ "$ROUNDCUBEMAIL_DB_USER" = 'root' ]; then
       : "${ROUNDCUBEMAIL_DB_PASSWORD:=${MYSQL_ENV_MYSQL_ROOT_PASSWORD}}"
@@ -35,7 +37,7 @@ if [[ "$1" == apache2* ]] || [ "$1" == php-fpm ]; then
     : "${ROUNDCUBEMAIL_DB_NAME:=${MYSQL_ENV_MYSQL_DATABASE:-roundcubemail}}"
     : "${ROUNDCUBEMAIL_DSNW:=${ROUNDCUBEMAIL_DB_TYPE}://${ROUNDCUBEMAIL_DB_USER}:${ROUNDCUBEMAIL_DB_PASSWORD}@${ROUNDCUBEMAIL_DB_HOST}/${ROUNDCUBEMAIL_DB_NAME}}"
 
-    /wait-for-it.sh ${ROUNDCUBEMAIL_DB_HOST}:3306 -t 30
+    /wait-for-it.sh ${ROUNDCUBEMAIL_DB_HOST}:${ROUNDCUBEMAIL_DB_PORT} -t 30
   else
     # use local SQLite DB in /var/www/html/db
     : "${ROUNDCUBEMAIL_DB_TYPE:=sqlite}"