diff --git a/README.md b/README.md
index 8401284..57aacd2 100644
--- a/README.md
+++ b/README.md
@@ -246,6 +246,22 @@ Stripping sender details
 
 SMF will strip the sender's IP, client, and user agent headers when the `SMF_SENDERPRIVACY` environment variable is defined.
 
+
+Custom postfix configuration
+----------------------------
+
+SMF allows to use environment variables to add or change lines to postfix `main.cf` and `master.cf` configuration files.
+
+- `SMF_POSTFIXMAIN_*` variables will edit postfix `main.cf` entries.
+  - Format: `SMF_POSTFIXMAIN_option_name=value`
+  - Example: `SMF_POSTFIXMAIN_soft_bounce=yes` will call `postconf -e soft_bounce=yes` and add the option.
+
+- `SMF_POSTFIXMASTER_*` variables will edit postfix `master.cf`.
+  - Format: `SMF_POSTFIXMASTER_service__name__type__parameter_name=value` Please note the double underscore `__` to differentiate service and type (which require a `/` as separation symbol) and the single underscore `_` used only by parameter names.
+  - Example: `SMF_POSTFIXMASTER_submission__inet__smtpd__recipient_restrictions=permit_mynetworks,permit_sasl_authenticated,reject` will call `postconf -P submission/inet/smtpd/recipient_restrictions=permit_mynetworks,permit_sasl_authenticated,reject` and add the option.
+
+
+
 Helper Scripts
 --------------------
 
diff --git a/VERSION b/VERSION
index 347f583..9df886c 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.4.1
+1.4.2
diff --git a/entrypoint.sh b/entrypoint.sh
index 8523947..62e58f8 100755
--- a/entrypoint.sh
+++ b/entrypoint.sh
@@ -20,6 +20,8 @@ Environment Variables:
     SMF_MYNETWORKS - configure relaying from trusted IPs, see http://www.postfix.org/postconf.5.html#mynetworks
     SMF_RELAYHOST - configure a relayhost
     SMF_SENDERPRIVACY - strips sender's IP, client, and user agent.
+    SMF_POSTFIXMAIN_* - configure any postfix main.cf variable
+    SMF_POSTFIXMASTER_* - configure any postfix master.cf variable
 
 this creates a new smtp server which listens on port 25,
 forward all email from
@@ -257,6 +259,21 @@ function start_postfix {
         echo "InternalHosts /etc/opendkim/TrustedHosts" >> /etc/opendkim/opendkim.conf 
     fi
 
+    echo "Postfix main.cf custom entries from SMF_POSTFIXMAIN_"
+    # Allow for setting any Postfix variables in the main.cf file through environment variables.
+    for e in ${!SMF_POSTFIXMAIN_*} ; do
+        OPT_NAME=$(echo ${e:16} | tr '[:upper:]' '[:lower:]')
+        OPT_VALUE=${!e}
+        echo "postconf -e "${OPT_NAME}=${OPT_VALUE}""
+        postconf -e "${OPT_NAME}=${OPT_VALUE}"
+    done
+    echo "Postfix master.cf custom entries from SMF_POSTFIXMASTER_"
+    # Allow for setting any Postfix variables in the master.cf file through environment variables.
+    for e in ${!SMF_POSTFIXMASTER_*} ; do
+        OPT_NAME=$(echo ${e:18} | tr '[:upper:]' '[:lower:]' | sed 's/__/\//g')
+        OPT_VALUE=${!e}
+        postconf -P "${OPT_NAME}=${OPT_VALUE}"
+    done
 }
 
 #
diff --git a/test/simple-mail-forwarder.bats b/test/simple-mail-forwarder.bats
index 015658b..843bd15 100644
--- a/test/simple-mail-forwarder.bats
+++ b/test/simple-mail-forwarder.bats
@@ -183,3 +183,21 @@
     done
     [ $? -eq 0 ]
 }
+
+@test "test custom main.cf entries" {
+    for e in ${!SMF_POSTFIXMAIN_*} ; do
+        OPT_NAME=$(echo ${e:16} | tr '[:upper:]' '[:lower:]')
+        OPT_VALUE=${!e}
+        ret=$(postconf | grep "$OPT_NAME" | grep "$OPT_VALUE")
+        [[ ! -z "$ret" ]]
+    done
+}
+
+@test "test custom master.cf entries" {
+    for e in ${!SMF_POSTFIXMASTER_*} ; do
+        OPT_NAME=$(echo ${e:18} | tr '[:upper:]' '[:lower:]' | sed 's/__/\//g')
+        OPT_VALUE=${!e}
+        ret=$(postconf -P | grep "$OPT_NAME" | grep "$OPT_VALUE")
+        [[ ! -z "$ret" ]]
+    done
+}