diff --git a/10-50-reverse.sh b/10-50-reverse.sh
index 296a55b..d6e2f94 100755
--- a/10-50-reverse.sh
+++ b/10-50-reverse.sh
@@ -16,10 +16,11 @@ ReverseServerName=aquarius.gw.fff.community.
 #################################################################
 
 function GetZoneFileSerial() {
-	local FirstSOALineAndFollowing="^/\S\+\s\+IN\s\+SOA\s/,\$!d;"
+	local INSOAPrefix="^\s*\S\+\s\+\([0-9]*\s\)\?\s*IN\s\+SOA\s\+"
+	local FirstSOALineAndFollowing="/""$INSOAPrefix""/,\$!d;"
 	local RemoveComments=":a;s/;.*$//g;"
 	local RemoveLineBreaks=":a;N;\$!ba;s/\n//g;"
-	local SearchPrintSerial="s/^\S\+\s\+IN\s\+SOA\s\+\S\+\s\+\S\+\s\+(\?\s\+\([0-9]*\).*/\1/"
+	local SearchPrintSerial="s/""$INSOAPrefix""\S\+\s\+\S\+\s\+\((\s\)\?\s*\([0-9]*\).*/\3/i"
 
 	local Serial=$(sed -e "$FirstSOALineAndFollowing""$RemoveComments""$RemoveLineBreaks""$SearchPrintSerial" "$1")
 	echo "$Serial"