ORA-31020 when using XML with external DTD or entities

Question

I'd like to parse XML documents against a modular DTD that references other DTDs. This works fine with Oracle 9i. But after upgrading to 11g, the parsing of XML-instances fails and DBMS_XMLPARSER.parseClob produces ORA-31020.
The same error occurs even if I simply try to store XML with a reference to an external DTD as xmltype:
SQL> select xmltype('<?xml version="1.0" encoding="iso-8859-1"?><!DOCTYPE ewl-artikel SYSTEM "http://www.foo.com/example.dtd"><test>123</test>') from dual;
ERROR:
ORA-31020: Der Vorgang ist nicht zulässig, Ursache: For security reasons, ftp
and http access over XDB repository is not allowed on server side
ORA-06512: in "SYS.XMLTYPE", Zeile 310
ORA-06512: in Zeile 1
How can I use external DTDs on remote servers in order to parse XML in an 11g database??? Any ideas for a workaround? Thanks in advance!

Answer 1

This is my PL/SQL validation procedure:
procedure validatexml (v_id in number default 0) is
PARSER DBMS_XMLPARSER.parser;
DTD_SOURCE clob;
DTD_DOCUMENT xmldom.DOMDocumentType;
XML_INSTANCE xmltype;
BEGIN
-- load DTD from XDB repository
SELECT httpuritype('http://example.foo.de/app1/DTD1.dtd').getclob() into DTD_SOURCE from dual;
-- load XML instance
select co_xml into XML_INSTANCE from tb_xmltab where co_id=v_id;
-- parse XML instance
PARSER := DBMS_XMLPARSER.newParser;
xmlparser.setValidationMode( PARSER , false);
xmlparser.parseDTDClob( PARSER , DTD_SOURCE , 'myfirstnode' );
DTD_DOCUMENT := xmlparser.getDoctype( PARSER );
xmlparser.setValidationMode( PARSER , true );
xmlparser.setDoctype( PARSER , DTD_DOCUMENT );
DBMS_XMLPARSER.parseClob( PARSER , v_xml );
DBMS_XMLPARSER.freeParser(PARSER);
htp.print('<P>XML instance succesfully validated!<P>');
end validatexml;