背景：
数据库由10.2.0.4升级到11.2.0.3.6后发送邮件报错。

原因：
      For database users upgrading to Oracle Database 11g Release 1 (11.1), applications that depend on the PL/SQL network utility packages compile without any issues. However, at runtime the applications might receive exceptions when attempting to perform. privileged network operations
     （当oracle数据库升级到11.1之后，应用程序依赖于PL / SQL网络实用程序包编译没有任何问题。然而,在运行时,应用程序可能会收到异常当试图执行特权网络操作）
      主要是一下几个包
     Normal 0 7.8 磅 0 2 false false false EN-US ZH-CN X-NONE

UTL_TCP

UTL_HTTP

UTL_SMTP

UTL_MAIL

  现象：
Normal 0 7.8 磅 0 2 false false false EN-US ZH-CN X-NONEORA-24247: network access denied by access control list (ACL)

解决方法：
    使用dba账户使用下面脚本授予报错账户访问外部网络服务，以SCOTT为例：

   Normal 0 7.8 磅 0 2 false false false EN-US ZH-CN X-NONEBEGIN

  -- Only uncomment the following line if ACL "network_services.xml" has already been created
  --DBMS_NETWORK_ACL_ADMIN.DROP_ACL('network_services.xml');

  DBMS_NETWORK_ACL_ADMIN.CREATE_ACL(
    acl => 'network_services.xml',
    description => 'NETWORK ACL',
    principal => 'SCOTT',
    is_grant => true,
    privilege => 'connect');

  DBMS_NETWORK_ACL_ADMIN.ADD_PRIVILEGE(
    acl => 'network_services.xml',
    principal => 'SCOTT',
    is_grant => true,
    privilege => 'resolve');

  DBMS_NETWORK_ACL_ADMIN.ASSIGN_ACL(
    acl => 'network_services.xml',
    host => '*');

  COMMIT;

END;