Did you enable NAT-Traversal? Check out this: http://www.cisco.com/en/US/docs/security/pix/pix63/configuration/guide/i psecint.html#wp1057446 http://www.rfc-editor.org/cgi-bin/rfcdoctype.pl?loc=RFC&letsgo=3947&type =http&file_format=txt Hope this helps.