diff --git a/Shorewall-perl/Shorewall/Config.pm b/Shorewall-perl/Shorewall/Config.pm
index 5368cbbd7..874c67aa2 100644
--- a/Shorewall-perl/Shorewall/Config.pm
+++ b/Shorewall-perl/Shorewall/Config.pm
@@ -875,10 +875,10 @@ sub read_a_line() {
 	    #
 	    # Expand Shell Variables using %ENV
 	    #
-	    while ( $currentline =~ /^(.*?)\$([a-zA-Z]\w*)(.*)$/ || $currentline =~ /^(.*?)\${([a-zA-Z]\w*)}(.*)$/ ) {
-		my $val = $ENV{$2};
+	    while ( $currentline =~ /^(.*?)\$({)?([a-zA-Z]\w*)(?(2)}|)(.*)$/ ) {
+		my $val = $ENV{$3};
 		$val = '' unless defined $val;
-		$currentline = join( '', $1 , $val , $3 );
+		$currentline = join( '', $1 , $val , $4 );
 	    }
 
 	    if ( $currentline =~ /^\s*INCLUDE\s/ ) {