Currently you may not embed commas (,) in a string. It is a known defect which was fixed by: 1213. [bug] fdupont Option string values containing comma can now be specified correctly by preceding comma with double backslashes (e.g. "foo\\,bar"). (Trac #5105, git fa79ac2396aa94d7bac91bd12d3593ebaaa9386d) Thanks Francis Dupont <fdupont at isc.org>