diff --git a/postinstall b/postinstall
index 6a3b3c5..e5b11ac 100755
--- a/postinstall
+++ b/postinstall
@@ -424,7 +424,10 @@ ask_mail_config(){
     fi
     recipientaddress=""
     smtphost=$(grep relayhost /etc/postfix/main.cf | cut -d : -f1 | cut -d ' ' -f3 | cut -d ']' -f1 | cut -d '[' -f2)
-    smtpport=25
+    smtpport=$(grep relayhost /etc/postfix/main.cf | cut -d':' -f2)
+    if [[ $smtpport == "" ]] || [[ $smtpport == "relayhost" ]]; then
+        smtpport=25
+    fi    
     username=""
     password=""
     if [ -f /etc/postfix/sasl_passwd ]; then
@@ -442,8 +445,8 @@ ask_mail_config(){
         if ! displayname=$(whiptail  --title "MAIL DELIVERY" --backtitle "$PROG" --inputbox "Please enter your sender display name." 9 76 $(hostname -f) 3>&1 1>&2 2>&3); then cancel_dialog; fi
         if ! recipientaddress=$(whiptail  --title "MAIL DELIVERY" --backtitle "$PROG" --inputbox "Please enter the email address to receive notifications." 9 76 $(pvesh get access/users/root@pam --output-format yaml| grep email | cut -d' ' -f2) 3>&1 1>&2 2>&3); then cancel_dialog; fi
         if ! smtphost=$(whiptail  --title "MAIL DELIVERY" --backtitle "$PROG" --inputbox "Please enter the servername of your smarthost." 9 76 $smtphost 3>&1 1>&2 2>&3); then cancel_dialog; fi
-        smtpport=$(inputbox_int 'MAIL DELIVERY' 'Please enter the port of your smarthost' 7 $(grep relayhost /etc/postfix/main.cf | cut -d':' -f2))
-        if ! senderaddress=$(whiptail  --title "MAIL DELIVERY" --backtitle "$PROG" --inputbox "Please enter your sender email address." 9 76 3>&1 1>&2 2>&3); then cancel_dialog; fi
+        smtpport=$(inputbox_int 'MAIL DELIVERY' 'Please enter the port of your smarthost' 7 $smtpport)
+        if ! senderaddress=$(whiptail  --title "MAIL DELIVERY" --backtitle "$PROG" --inputbox "Please enter your sender email address." 9 76 $senderaddress 3>&1 1>&2 2>&3); then cancel_dialog; fi
         if whiptail --title "MAIL DELIVERY" \
         --backtitle "$PROG" \
         --yes-button "CONFIGURE AUTH" \