diff --git a/postfix/Dockerfile b/postfix/Dockerfile
index d97f45b..430e259 100644
--- a/postfix/Dockerfile
+++ b/postfix/Dockerfile
@@ -2,6 +2,7 @@ FROM alpine:edge
 
 RUN apk add --no-cache \
 	bash \
+	ca-certificates \
 	libsasl \
 	postfix \
 	rsyslog \
diff --git a/postfix/service/postfix/run b/postfix/service/postfix/run
index b99e082..eddc9e8 100755
--- a/postfix/service/postfix/run
+++ b/postfix/service/postfix/run
@@ -1,44 +1,44 @@
 #!/bin/bash
 set -e
 
+# Avoid  warning: smtputf8_enable is true, but EAI support is not compiled in
+echo "smtputf8_enable = no" >> /etc/postfix/main.cf
+
 # Do we want to modify the config first with the script?
 [ -f /etc/service/postfix/run.config ] && source /etc/service/postfix/run.config
 
-if [ "$MAILNAME" ]; then
+if [[ ! -z "$MAILNAME" ]]; then
 	echo "$MAILNAME" > /etc/mailname
 	postconf -e myhostname="$MAILNAME"
 fi
 
-if [ "$MY_NETWORKS" ]; then
+if [[ ! -z "$MY_NETWORKS" ]]; then
 	postconf -e mynetworks="$MY_NETWORKS"
 fi
 
-if [ "$MY_DESTINATION" ]; then
+if [[ ! -z "$MY_DESTINATION" ]]; then
 	postconf -e mydestination="$MY_DESTINATION"
 fi
 
-if [ "$ROOT_ALIAS" ]; then
-	sed -i '/^root:/d' /etc/aliases
+if [[ ! -z "$ROOT_ALIAS" ]]; then
+	if [[ -f /etc/aliases ]]; then
+		sed -i '/^root:/d' /etc/aliases
+	fi
 	echo "root: $ROOT_ALIAS" >> /etc/aliases
 	newaliases
 fi
 
-if [ "$RELAY" ]; then
+if [[ ! -z "$RELAY" ]]; then
 	# setup the relay
 	echo "relay_host = $RELAY" >> /etc/postfix/main.cf
 fi
 
-if [ "$SASL_AUTH" ]; then
+if [[ ! -z "$SASL_AUTH" ]]; then
 	# setup tls
-	echo -e "smtp_sasl_auth_enable = yes\nsmtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd\nsmtp_sasl_security_options = noanonymous\nsmtp_use_tls = yes" >> /etc/postfix/main.cf
-
-	# Avoid  warning: smtputf8_enable is true, but EAI support is not compiled in
-	echo "smtputf8_enable = no" >> /etc/postfix/main.cf
+	echo -e "smtp_sasl_auth_enable = yes\nsmtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd\nsmtp_sasl_security_options = noanonymous\nsmtp_use_tls = yes\ninet_interfaces = 127.0.0.1" >> /etc/postfix/main.cf
 
 	# generate the SASL password map
-	cat > /etc/postfix/sasl_passwd <<- EOF
-	$RELAY $SASL_AUTH
-	EOF
+	echo "$RELAY $SASL_AUTH" > /etc/postfix/sasl_passwd
 
 	# generate a .db file
 	postmap /etc/postfix/sasl_passwd