diff --git a/postfix/start.sh b/postfix/start.sh
index a0353e16..14ad6367 100755
--- a/postfix/start.sh
+++ b/postfix/start.sh
@@ -2,7 +2,7 @@
 
 # Substitute configuration
 for VARIABLE in `env | cut -f1 -d=`; do
-  sed -i "s,{{ $VARIABLE }},${!VARIABLE},g" /etc/postfix/*.cf
+  sed -i "s={{ $VARIABLE }}=${!VARIABLE}=g" /etc/postfix/*.cf
 done
 
 # Actually run Postfix