diff --git a/conf/postfix-service.sh b/conf/postfix-service.sh
index 5d58a24..64084d7 100755
--- a/conf/postfix-service.sh
+++ b/conf/postfix-service.sh
@@ -7,7 +7,8 @@ function log {
 function serviceConf {
   # Substitute configuration
   for VARIABLE in `env | cut -f1 -d=`; do
-    sed -i "s={{ $VARIABLE }}=${!VARIABLE}=g" /etc/postfix/*.cf
+    VAR=${VARIABLE//:/_}
+    sed -i "s={{ $VAR }}=${!VAR}=g" /etc/postfix/*.cf
   done
 
   # Override Postfix configuration