ora创建数据库连接

1 环境
  在 小机 上 执行下面的代码  create public database link SCM10013
  connect to ljscm  IDENTIFIED BY wwwwwasljscm
  using '(DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.100.13)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = scm)
    )
    )';小机的ip是 101.13  
PRODUCT                                     VERSION          STATUS
NLSRTL                                      10.2.0.4.0 Production
Oracle Database 10g Enterprise Edition       10.2.0.4.0 64bi
PL/SQL                                      10.2.0.4.0 Production
TNS for IBM/AIX RISC System/6000:           10.2.0.4.0 ProductioIBM AIX（Advanced Interactive eXecutive）是IBM开发的一套UNIX操作系统100.13 是 winserver 2008 
PRODUCT                                     VERSION          STATUS
NLSRTL                                      10.2.0.4.0 Production
Oracle Database 10g Enterprise Edition       10.2.0.4.0 64bi
PL/SQL                                      10.2.0.4.0 Production
TNS for 64-bit Windows:                    10.2.0.4.0 Production在小机中执行 select * from ljscm.aa@SCM10013
报错误 ora_12543: tns:destination host unreachable