12170 oracle连接有关问题

12170 oracle连接问题
局域网（内网）可以连接没问题，外网最近两天连不上（以前能连），报以下错：
Fatal NI connect error 12170.

  VERSION INFORMATION:
TNS for 32-bit Windows: Version 10.2.0.1.0 - Production
Windows NT TCP/IP NT Protocol Adapter for 32-bit Windows: Version 10.2.0.1.0 - Production
  Time: 22-7月 -2011 10:09:30
  Tracing not turned on.
  Tns error struct:
  ns main err code: 12535
  TNS-12535: TNS: 操作超时
  ns secondary err code: 12560
  nt main err code: 505
  TNS-00505: 操作超时
  nt secondary err code: 60
  nt OS err code: 0
  Client address: <unknown>


ora配值 (外网 xmbw.vicp.net 为域名)如下：
xmbwvicpnet =
  (DESCRIPTION =
  (ADDRESS_LIST =
  (ADDRESS = (PROTOCOL = TCP)(HOST = xmbw.vicp.net)(PORT = 1521))
  )
  (CONNECT_DATA =
  (SERVICE_NAME = orcl)
  )
  )


------解决方案--------------------
具体是否做了端口映射。
------解决方案--------------------
把域名改成IP地址试试
------解决方案--------------------
没改机器名吧