diff --git a/unix/vncserver b/unix/vncserver
index 23e127d..ecdec9e 100755
--- a/unix/vncserver
+++ b/unix/vncserver
@@ -1871,7 +1871,7 @@ sub DefineConfigToCLIConversion {
               isValidCallback => sub {
                 my $value = shift;
 
-                return 0 unless $value =~ /^\d+$/;
+                return 0 unless $value =~ /^-?\d+$/;
 
                 $value >= -359 && $value <= 359;
               },